-( Story related, cannot be missed )-
While I may have bare facts, I have at least taken the liberty of giving you a full walkthrough to complete this. This is a story-related achievement, therefore you cannot complete the game without actually getting this.
*** Spoiler - click to reveal ***Act 1: Sweet, Sweet Magic
Part 1a: Free Abracadaniel from Jail
Start the case by standing in front of the Candy Kingdom. Head to the right and use Jake on the ledge leading down into the moat. The Banana Guards will tell you your next hint: break the rusted pretzel grate to get in to the kingdom. After Combat Time, you can talk to your first snail right near where the path leads north. Head in to the castle and go talk to Bubblegum to get access to Peppermint Butler's room. Once inside, investigate the room to find out what happened. You'll need to talk to everyone (Banana Guard, Starchie, Gumball Guardian), uncover all of the clues (jellybeans, leaf, and bubble wand), then head into the security room to talk to Bubblegum. Once you clear Abracadaniel by answering her questions, head into the jail beside the security room and use Jake to get the keys above the Banana Guard. Open the cell door only to find that he will not leave without his Cake Plate and a means of leaving the Kingdom safely.
Part 1b: Abracadaniel's Great Escape
Abracadaniel says that Peppermint Butler was using his plate last, so we must return there. However, there is nothing new compared to last time. Chet will also be mentioned as possibly having the plate, so that will be our next visit. Leave the palace and head north. You'll find a snail on the way up there before coming to Chet's house, currently being occupied by gnomes. Use Jake to pick up the nearby beehive, then use him again to get onto the roof and drop the beehive down the chimney. After the fight, head in and find a note from PBut as well as a book of matches.
Return into the palace and head to the kitchen, following the tip earlier about the leaves. Pick up some soap, cake candles, and the empty plastic bottle. Combine the soap with the bottle, then use the bottle on the sink. Combine the full bottle with the bubble wand to get a full bottle of bubbles. Take the candles back to PBut's room and use them and the matches on the candlestick on his bookshelf. This will reveal PBut's secret room and, within, the cake plate. Now return to the kitchen and head to the Banana Guard heading to the balcony. Show him the BG182 card to get access to the balcony and, from there, use the bottle of bubbles with the updraft to make a way out. All that's left is to leave with Abracadaniel to Wizard City!