Stitch & Ai follows the events of Leroy & Stitch. Stitch is kidnapped by space criminals who want to use him to have their own destructive genetic experiment. However, he escapes to China's Huangshan mountains, where he befriends Ai, a spirited local girl who is at risk of being separated from her older sister Jiejie. Stitch becomes Ai's "dog", and the two help each other in dealing with the other's problems; Ai helps Stitch deal with the space criminals, while he helps her stay in the mountains with her family.