Bay spends an evening drinking with Tank but cannot remember her actions from that night; Daphne is invited to a student gathering at professor Marillo's home; Lily offers to help Toby.

Switched at Birth tells the story of two teenage girls who discover they were accidentally switched as newborns in the hospital. Bay Kennish grew up in a wealthy family with two parents and a brother, while Daphne Vasquez, who lost her hearing at an early age due to a case of meningitis, grew up with a single mother in a poor neighborhood. Things come to a dramatic head when both families meet and struggle to learn how to live together for the sake of the girls.