Japanese maestro Kore-eda maintains the intense focus on children's relationships with their parents that distinguished his recent work - Nobody Knows, Still Walking and I Wish - with his new film, which approaches a subject popular with filmmakers: the plight of the families whose babies are switched at birth.
Last year's French-made drama The Other Son added the extra element that the families were Israeli and Palestinian; here, the divide is one of social class.
Workaholic architect Ryota Nonomiya (Fukuyama) drives his 6-year-old son Keita (Ninomiya) with a cold ambition verging on fanaticism. When his compliant wife Midori (Ono) says the local hospital has called them in, Ryota expresses the hope that "nothing messy" will disrupt his regimented life, but he's out of luck.
Keita, it transpires, is the biological son of Yudai and Yukari Saiki (Franky and Maki), home appliance dealers in a dreary outer suburb. The Saikis have been raising the Nonomiyas' real son, Ryusei (Sho-gen).
Kore-eda's screenplay lays all this out in the opening 20 minutes or so: the film's real pleasures lie in watching the way the six characters deal with the situations and how their different responses resolve and shift over time.