When Jake has to get Lady Rainicorn on the train to cure her illness, they'll come across some shady characters on the Ooorient Express! Lady Rainicorn has come down with a case of taffy fever and there is nothing Jake can do to help her. After many failed attempts with Princess Bubblegum, Finn and Jake learn of a special cure that can help Lady Rainicorn get back to normal. The catch? They will have to travel on the Ooorient Express on an infamous train ride that no one returns from!