As part of an intergalactic coalition, a well-meaning space alien volunteers to bring a message of self-actualization and harmony with nature to the one planet rejected by all her peers as incorrigible: Earth.
In Paris in 1935, a young Jewish woman married to an anti-fascist activist befriends her neighbor who is dating a far-right supporter.
Ariane lives with Simon in his large Paris flat. Simon is obsessed with her: he wants to know everything about her, secretly follows her when she goes out, asks questions all the time, even in the most intimate moments. Ariane seems to take it all in stride, but Simon realises that she's hiding something.