An affluent, middle-aged couple’s uneventful lives are forever changed when they move into an isolated house in the country and befriend an odd, younger couple.

It’s 1941, but France is trapped in the 19th Century, governed by steam and Napoleon V. Avril, a teenage girl, goes in search of her missing scientist parents.

Thirteen-year-old Bastien is the center of a reconstructed family: 6 half-brothers and sisters, 8 “parents,” and as many houses. His tasks within the family are far more complex than what…