Montalbano has a strange dream: in the middle of a field there is a coffin with a dead man. The commissioner is horrified: police chief Bonetti Alderighi is lying in a coffin...In the morning, two new cases are waiting at the Montalbano commissariat. The owner of a large supermarket, Signor Di Marta, wants to file a report about the robbery of his wife. The Commissioner feels that something is wrong here... Meanwhile, an elderly peasant discovers a door in his old abandoned house that was not there before. Arriving at the place, Montalbano and his comrades notice fresh signs of the presence of strangers and traces of a weapons warehouse. The commissioner sends the findings to the counter-terrorism department, but decides to simultaneously conduct his own investigation.