Noah Selvaggio is a retired chemistry professor and widower living on the Upper West Side, but born in the South of France. He is days away from his long-awaited first trip back to Nice, but he receives a call from social services: Noah is the closest available relative of his eleven-year-old great-nephew and he urgently needs someone to take him in.

Plagued by guilt and a feeling of duty to his dead sister, Noah agrees to foster the kid 'just for couple of weeks' and takes him along on his visit to Nice. This unlikely duo, both feeling adrift in their lives and suffering from culture shock, argue about everything from steak frites to Snapchat.

Noah is disappointed by how much Nice has changed since he left. When sharp-eyed Michael identifies the historic Hotel Excelsior in one of Noah's photographs, they decide to check in - but once inside their luxury suite, Noah's perception of his ancestral heritage starts to crack.

Shocking stories of the Nazi occupation surface: a hotel re-purposed for torture, a secret resistance movement, and Noah's mysterious mother on the front lines of history. As dark truths about this famous tourist mecca come to light, Noah learns to appreciate Michael's street-smart wit and ease with technology. He finally grasps the great risks people in all ages have taken for their kin.