4 and a half is the apartment occupied on the Plateau Mont-Royal in Montreal by a young couple. It is a chronicle of the daily life of the urban reality of 25-30 year olds: love, friendship, humor and tenderness.

A young girl is orphaned when her nurturing grandmother enters a nursing. She is sent to live with her Bach-obsessed uncle, an organist preparing for an important recital.

In the early 1940's, Canada is a country at war and Florentine is a young woman, from a very poor family, looking for love. She meets two suitable men, a nice soldier from a good and wealthy family, and an ambitious self-centered engineer. She must decide whether she wants to follow her head or her heart...