An Icelandic volcano has blocked air traffic and Thelma’s parents are stuck overseas. Until planes start flying across the sky again Jean, Vincent and Thelma share the same roof.

Alex and Noémie, in their thirties, would like to have a child. But their plans are turned upside down when Alex's mother, Suzanne, starts doing crazy stuff. It's because she has contracted 'semantic dementia', a fatal neurodegenerative disease that affects her behavior. She spends lavishly, pays nightly visits to her neighbors to eat sandwiches, makes herself a fake driver's license with glue and scissors. Suzanne the mother goes to Suzanne the unmanageable-kid. A strange school of parenting for Noémie and Alex.