One Last Job is the 23 episode of Season 5 and the 127th of Adventure Time. It aired June 10, 2013.
The episode starts off with Jake sitting in the boat at the top of the Tree Fort and saying how the male birds are so much nicer than the females and the females are all plain. A bird flies up to him and tells him that the female birds are beautiful on the inside. He says he has a special delivery for Jake, it is a tape that says "URGENT. Watch now."
Jake goes into the tree house, and gets BMO to play the tape. He sees a person being held hostage and wonders what he is watching. The bag is taken off the person's head, and Jake Jr. struggles to try to get free. Jake gasps and becomes enraged. The mystery man tells Jake that he/she knows about Jake's criminal past, and that he has to get his old gang back together to steal the purest form of sugar; the "Baker's Shard".
Jake changes his appearance into a more sinister one. He tells BMO not to tell Finn about what he's doing. Then, he presses a button which alerts all of the members of his old gang - Tiffany, the Flying Lettuce Brothers and Gareth - it's time for them to have a meeting.
The members gather, where Jake tells them what the situation is like. Tiffany expresses the will to battle Finn, but Jake tells him not to get him in the mess, leading to a scene where Finn is randomly playing instruments and talking to BMO. The gang members are having a fight, with the others thinking Jake has gone soft. However, Jake manages to convince them to steal the Baker's Shard.
At the Candy Kingdom, the Captain Banana Guard and the Private Banana Guard are awaiting their shipment of milk. Disguised as milkmen, Gareth and the Flying Lettuce Brothers enter their room and put the captain to sleep. Mimicking the captain's voice, the Flying Lettuce Brothers force the Banana Guards to go outside and shout as much as they can, taking away their attention from the Baker's Shard.
Knowing the place well, Tiffany tells Jake how to get to the Baker's Shard. After avoiding a series of traps, Jake reaches the Baker's Shard. On the other side of the hall, he hears the voice of his daughter's kidnapper. Throwing to him the Baker's Shard, it is revealed the voice from Flying Lettuce Brothers, who have been using a different voice.
Angered, Jake grows extremely large, chasing the milk van they came with. After finally catching, Jake finds out that the van was driven by Jake Jr. herself. After the gang runs away, Jake Jr. reveals she heard stories from her mother about Jake's criminal days. This gave her an inspiration to trick her dad and make him proud. Jake tells her that what he did was wrong and he isn't doing it anymore. The episode ends with Jake and Jake Jr. walking into the sun, going toward the Tree Fort.