For some time now, some kind of black streak has been haunting the Merdalor liner. On every cruise, one of the passengers mysteriously disappears. To avoid scandal, the president-CEO of a cruise line wants a horde of cops to spend their vacation aboard his ship. Everything is free: caviar, lobster, the best wines. For complete happiness, you can take with you your wives, children, sick mothers-in-law, weak-minded aunts, the whole family with a bob, a canary, and indoor flowers. On one condition: look into all the cracks...And they boarded this ship...