Following the end of the Head of the Class series, Billy moves to Berkeley, California, where he marries Mary Springer, a single mom with several children, so he could get his green card. The marriage is arranged in order to prevent Billy from being deported back to the UK. Billy becomes Mary's boarder, living in her basement apartment with the strictest of rules: no drinking, no smoking, no pets, and no sex. The series follows Billy's misadventures as he adjusts to life in California while staying one step ahead of immigration officials seeking to prove his marriage is a sham. Meanwhile, his relationship with Mary's children, 14-year-old David, 10-year-old Laure, and 5-year-old Annie, deepens to a parental level, and Billy and Mary likewise find themselves drawing closer together, although the series was cancelled before this subplot could be carried out.