Commissaire Maigret investigates the murder of a former ambassador in the Quai d'Orsay, and its connection to a decades long affair with a recently widowed princess.
André Masson, specialist in modern art, receives a letter according to which a painting by Egon Schiele had been discovered in Mulhouse. He finds that the work has been missing since 1939. This discovery puts his career in danger.
A 23-year-old girl is contacted by an unknown life form claiming to be able to bring her older brother, who disappeared during a space mission, safely back to Earth.
