The Binary Bard is revealed as "King Mordred, Master of the Universe". (see related question)
Done!
no
Sorry, but no. No they can not. It is imposable. The only way to get it back is to do it all over again.
it matters what you've done
The Princess isn't there. Sir Gawain will accompany you as you complete the other two planets. Once all three are done, you get a clue to the location of the Binary Bard's hideout.
You travel to each of the three planets that the Queen gave you the coordinates to, overcome the challenges of all three planets, and meet with the three knights. After all of the planets are done, the Princess's location can be found. (see related questions)
There is no reason to get rid of the librarian and his guards. You have already done all you can do in the dungeon. You opened the back gate of the cell, which connects to Mordred's secret underground lab. Go there and you can enter the cell from the rear. (see related question)
I an not help you if you lost your game but I can find a solution. In the bottom right hand corner of the Poptropica game screen there is a save button. Click the button when you are done playing so when you return the next time you can continue with the game.
You have done exactly the right thing. You must defeat all three planets, and have all three knights with you, before you can rescue the Princess. The Knights will tell you of a giant asteroid where a portal to another galaxy exists. That asteroid is at X-11 Y-82 and with the three knights you can go there and pull the Golden Key from the crystal, opening the path to the distant galaxy where the Binary Bard has taken the Princess. (see related question)
you have to get by the last egg and once it pops up you jump up at the same time and it will push you over on the cage. You then click on the cage and then click it again. Once you have done that the green knight will say look out the mother is coming and you have to try to get passed all the bumble bees.
the puzzles are done
You can find the unowns inside the tanoby chambers which are located at the bottom of seven island you will need surf to reach them.