Over the course of the game, we learn about Mordred, a brilliant Da Vincian scientist in the Kingdom of Arturus. He was praised for bringing technology to Arturus but started tampering with nature, building cybernetic owls and mice. The king and queen banished him for his act of doing these things. He was locked up in the dungeon, but he escaped and did his work in secret. When the guards caught him, he escaped again into space with an unfinished rocket. Everyone thought he died in space, but the daughter of the king and queen thought otherwise. She joined a group loyal to Mordred and soon after that, the aliens abducted her. Now you must save her from Mordred, who has become a cyborg named Binary Bard.
You’ll arrive in the Kingdom of Arturus on Main Street. First, go a little bit to the right and you'll see a fountain. Jump to the water near the base of the spaceship and you will discover a Golden Coin. Now enter the "Mordred's Museum" next to the fountain. The man inside will not let you explore the museum unless you have one gold coin. Give him the one you found in the fountain, and now he will let you look around. After he gives you permission to look around he will give you a museum pamphlet. Next, click on one of the books and the guy will ask you not to touch them, but will give you a Library Book Slip. Pay attention to the underlined parts: McM.
Now, go outside and run all the way to the right until you find the Castle. Enter it, walk to the right, and enter the first small wooden door you see. You will find yourself inside the castle library. There are two books to get. To pick them up, just walk over them. One is a green book on the far left side of the room in the Fiction section. It is called The Mystical Weapons of Arturus. The second book is The Life of Mordred: A Cautionary Tale. It is down the stairs in the non-fiction section on a book stand. After you get the second book, look at the nameplates on the shelves. One is labelled McM, just like the underlined section of the library book slip you got earlier. Click on the brick behind the nameplate and a secret staircase in the floor will open up.
Go down the stairs and you will arrive in an underground room. Collect the Moldy Cheese on the floor. Then walk a little farther to the right and click on the wooden handle on the wall. This will open up a small grate near the ground inside the cell. You will also notice that there's a robot inside the cell.
Return to the library and the librarian will be waiting for you with two guards, unhappy with you for snooping around. Leave the library and return to the main part of the castle. Go to the left and enter the door by the staircase. There is a Mechanical Mouse on the ground. Use the moldy cheese to catch the robot mouse. Once you've done that, grab the Secret Message on the chest and leave the room. Go up the stairs and enter the door at the very top. You’ll find the King and Queen. Ask the Queen if she can think of anything else that might help you and she will give you the Coordinates of the three knights who left in search of the princess. The coordinates are X-73 Y-83, X-15 Y-15, and X-83 Y-20.
Ye Olde Rumour Mille
Leave the Castle, go to the right, and talk to the hooded guy near the entrance. He will give you a Bag of Manure. Go a little bit more to the right and enter Ye Olde Rumour Mille. Now jump up and you will see a piece of rope hanging to the right. Jump onto this rope, and this will lift the wooden rod so that it is no longer attached to the gears. Slide down the rope and you'll land on a platform with a black-haired woman next to you. Talk to her and she will ask to trade secrets and will take the secret message you found earlier. In return, she will give you a piece of paper with three Cosmic Symbols on it.
Go outside and you'll see that next to mill is a big wheel in the mud. On top of that wheel is a Coil of Rope. Jump up on the wheel to get the rope. Now walk over to the left and jump up on top of one of the windmill blades to get it to start spinning. As they spin to the left, a little glass bubble on the roof will start opening. Keep doing this until the glass bubble is completely open so you can get inside of it.
Inside the windmill, you will find a hovercraft. Use your bag of manure to power it. The hovercraft will fly out of the roof and land in the mud outside.
The Princess’ Tower
Head back to the castle and jump up onto the platform with the large bow and arrow on it. Use the rope and it will be attached to the arrow. Now point the arrow in about a 45-degree angle to the left, and click to shoot the arrow. If you aimed correctly, the arrow will stick into the door of a nearby tower. Now walk across the rope and enter the door in the tower.
Go to the left past the bed and grab the Princess' Note inside the chest.
The Secret Entrance
Go back to the fountain and click on the plaque on the wall that has the space symbols. Select the symbols in this order: Crescent Moon, Planet with Rings, 5-pointed star. Then click on the large Sun in the middle and a secret door will open. Go inside.
You've found a secret order. Walk to the right and talk to the boy with buck teeth and pimples. He will give you a Small Key.
Mordred’s Secret Hideout
Return to Mordred's Museum. Go up onto the top floor and click underneath the bed. You’ll find a Missing Page from Mordred's Journal.
Leave the museum and go back to the guy who gave you the manure. Next to him are two bales of hay. Push them away and you will reveal a secret locked trap door in the ground. Use the small key to open it.
Go down the rope, then walk up to the mechanical owl and it will fly outside. Follow it and then release the mechanical mouse and the owl will fly down and eat it. Now the owl will follow you around. If you click on the owl you can tell it where to fly.
Go back down, walk all the way left and keep pushing against the wall. After a few seconds, it will crumble into pieces. Go all the way to the left and you will see a small hole. Go through it to enter the cell where you earlier found the robot. He will self-destruct and a Fuel Rod will fly to the left beyond the bars. Click on the owl and then click on the fuel rod and the owl will retrieve it for you. Click on the owl and then click on yourself and your owl will give you the rod.
The Space Craft (Excalibur)
Go back outside and go all the way right until you see the hovercraft that you found earlier. Jump onto the hovercraft and head to the right. You will find a spacecraft named Excalibur. Click on the spacecraft and you will see a control panel. Drag the fuel rod in the bottom left corner to where the broken one is. Then enter the coordinates for the moon that you found earlier in the missing page of Mordred's Journal. They are x-56 and y-52. You enter the coordinates by spinning the two dials on the right. Once you’ve done that, press the red Launch button to take off.
The Excalibur will run out of fuel and crash land on the nearby moon. Go to the right, go up on the platform and enter the Astrozone building. Ask the guy on your left how to get off this planet. He’ll tell you to leave your ship for scrap and then build a new one on the holopad.
Go outside and click on the Holopad machine to the left.
When you like your ship, click on the Done button and enter your new rocket ship.
In the Rocket
Click on Launch to take off into space. To fly the ship, just move your mouse cursor around. You can shoot your weapon by clicking. Pay attention to the coordinates in the bottom left. When you get into alien space, watch out because other ships may start to attack you. There are three planets to visit and you can do them in whatever order you like.
The coordinates for Jungle Planet are 15,15. Once you arrive on land, exit your ship onto a platform, then drop all the way down onto the ground and walk to the right to grab the Laser Lance.
Next, go to the left and jump on top of one of the flowers. They will catapult you into the air. Keep jumping until you reach your spaceship again. Now jump through the swinging pendulums on your right avoiding the electrical bugs until you get on the platform on the right. After that, go to the right.
Next, you’ll find Sir Cador, who's failed in his rescue of the princess. Talk to him and he will tell you that you should try to get into the cage to save the princess. Go up the rope and then jump on the four eggs without being caught by the giant birds inside them. After that, jump onto the cage. There's a unicorn inside. Click on the cage to open it and then click on the Unicorn. Then Sir Cador will say that the Mother Phoenix is coming.
Now you're going to be up on the unicorn and flying him with your mouse. You need to avoid the flying bugs, rocket missiles, and lightning clouds. You can shoot the bugs with your laser lance by clicking on the mouse. After a while, the mother phoenix appears. She will open her mouth and then you need to shoot a fully charged shot (by clicking and holding your mouse until the tip lights up green) from your laser lance and hit her in the head.
After you hit her three times, she will destruct and you will return to Sir Cador. He will now accompany you on your mission. Once you are back in your ship, click Launch.
The coordinates for Fire Planet are 83,20. Once you land on the planet, exit your rocket ship.
You will be standing outside on a platform surrounded by hot lava. If you fall into the lava, you will be sent back to the starting platform. Move to the right, jumping from platform to platform. When you get to the final platform, wait for it to get to the top of the volcano and then jump off to the left. Once you land at the top of the volcano crater, go down inside.
Once you’re inside the volcano, you need to make your way through the caverns while avoiding the yellow steam that goes by. If you are touched by the steam, you get sent back all the way to the beginning and have to start over again. There are little alcoves along the way where you can wait safely for the steam to pass. As soon as it disappears, make your move to the next safe spot. Once you get to a larger open area, the steam stops coming. But now there is a rolling rock creature that blocks you from passing. Time your jump to go over him just as he's rolled up into a circle and you should be able to get by. Once you get past him, you’ll meet up with Sir Pelasus. He will tell you that he failed and that a beast is holding the princess. He will give you an Ice Arrow to slay the beast.
Now enter the room on the left, and you have to battle Dragotank. Jump up and climb the first chain to the top. Then move from chain to chain until you reach the end. Drop down and run under the dropping spike ball from the dragon's tail. Then click on the lever to temporarily shut down the robot dragon. Move quickly to the right, click on your ice arrow and shoot it into the dragon's mouth. Do the same thing 2 more times and you will defeat him.
Once you beat the mechanical dragon, Sir Pelasus will join you on your mission.
The coordinates for the Ice Planet are 73,83. When you arrive, you will find 3 space sharks guarding the planet. You need to lure them into a trap. Shoot all of them to get them to follow you and then lead them to the black hole located to the north. The coordinates for the black hole are approximately 84,47. When you’re luring them away, keep them close enough to stay on screen or they'll go back.
Once the space sharks have been dealt with, you can land the ship on the Ice Planet. When you exit the ship, you’ll be standing on a platform above ice water. If you fall into the water, you’ll be teleported back to your ship. Move from platform to platform while watching out for the flying robot fish.
Now jump up on the platforms to climb the mountain while avoiding the giant snowballs. Sir Gawain is standing at the very top of the mountain. Talk to him and he will give you a Force Shield. You will then have to fight a giant tiger-shaped helicopter that drops snowballs on you. Using the force field, you can bounce the snowballs back at him to damage the helicopter. You need to hit him three times. From time to time, ice shards will fly towards you and they will damage your shield, so watch out. If the shield runs out it will need to recharge and you will be defenceless for a while. After you defeat the tiger helicopter, Sir Gawain will appear and he will join you.
Go back into your ship and click the "Launch" button.
The Crystal Gate is an asteroid at the coordinates 11,82. You can go there once you've found all three knights. Once you land, exit the spacecraft. Climb up the crystal mountain to the top where the 3 knights are waiting. Click on the key that is stuck in the stone. You will open a small vortex that you can enter.
You'll arrive at the castle of the Binary Bard. Jump down to the bottom of the castle and speak with the princess. She will ask for the three powerful weapons you have brought and then she will take them from you. But once she does, she will reveal herself as the Binary Bard in disguise. He will then laugh at you and disappear.
Click on the wall next to you and it will become a puzzle. When you click on a square, it will stay the same but flip over the adjacent squares. The goal is to turn over all of the pieces. You have to click the boxes number 7, 8, 5, 6, 10, 11, 16, 15, 14, and 13. Now enter it. You can skip the puzzle by not talking to the princess and press enter in front of the door.
The Final Mordred Battle
Now first you will fly around as Merlin. The goal is to pick up the black bombs that Mordred drops on the ground and then fly above him. When they start blinking red, wait a few seconds and then release them so that they explode on him. When you get two bombs on Mordred, he will zap and destroy Merlin.
Now try to get Mordred close to the platform where the real princess is trapped. Then jump up on him and then up onto the platform. Stand on the edge and then do a big jump to either the left or the right. If you timed it right, you’ll land on one of the chandeliers. Now move so you are in the middle. He will go underneath the chandelier and fire his laser at it. It will fall on top of him. Repeat this on the other chandelier and then you will destroy Mordred. After that, you will automatically return to Arturus. A message will appear on the screen saying to go to the castle throne room. There you will be Knighted and given the Island Medallion. Congrats! You have now completed Astro Knights Island!
In Astro Knights there is a space mini game that lets you go to several planets. Here are the planets and areas.
On the Mechanical Jungle
- Jungle Floor
- Bird Area
On the Fire Planet
On the Ice Mountain
On The Magic Asteroid
- This island was briefly mentioned in Back Lot Island when a movie producer says he has an idea for a movie about sci-fi mixed with medieval, and your Poptropican claims that it had already been done.
- The island plot has many resemblances to Lunar Colony Island:
- Both of your mission is the same: finding a female that is lost somewhere in outer space.
- Both missing girls (the Princess and Salerno) are fans of outer space.
- Both islands took place in outer space.
- Both islands involve an asteroid belt.
- Both islands partly take place on the Moon (not really took place on the Moon in Astro Knights Island, but you can visit the Moon).
- You will launch and ride a rocket, and do it by yourself in both islands.
- Both of your first vehicles will break and you will never use it again.
- Both of your first vehicles will crash and break.
- Both of your first transportation vehicles will be broken in the middle of your trip (in Astro Knights, your rocket will get damaged if you get hit by alien or get hit by asteroids).
- Somebody in both islands will send you to rescue a girl that had a relationship with someone related to who sent you.
- Both islands got something to do with aliens (in Astro Knights you will meet aliens in Pewter Moon).
- Both themes are search and rescue.
- This Island came with the Dark, Love, and Earth Astro-Knights costumes.
- The captive robot alien in the castle dungeon says '01100010 01100001 01110010 01100100' which translates to 'bard', in reference to the Binary Bard.
- The robot invader being held captive in the dungeon is kept highly confidential, similar to the conspiracy that the American government is holding aliens captive in Area 51.
- Astro-Knights Island seems to have taken place in the 1000s and the 1100s, since those are real knight eras.
- It is said to be Poptropica's hardest island.
- Poptropica released an in-game walkthrough of this island on August 11, 2011. However, this was removed after the Astro-Knights novel came out.