A terrorized Leela is held captive, by a mouse, in the bathroom of her New York City studio apartment. She attempts many humorous methods to rid herself of the mouse but finally, at her mother's opportunistic urgings, decides to leave the city once and for all to move back to Indiana. As she finishes her packing a neighboring boy comes to visit and say good-bye. It becomes apparent that the title, My Mouse, applies not to Leela as we supposed but to the little boy. For as he laments that all his friends keep leaving him, Leela realizes that his "friends" were his pet mice...who ran away to her apartment. An epiphany pronounced with the snap of a mousetrap!