Keka, daughter and granddaughter of sailors, skips school one day to go down to the port to say hello to her father, captain of the tug boat Antares and, while she’s there, see Abdú, the boy she fancies. When she arrives, the boat is deserted. She goes on board and lies down on a bunk to wait for them but she falls asleep. By the time she realises, the tug has set out to the rescue of a shipwreck. Since he cannot return to port, the captain must complete his mission with his daughter on board, an unpredictable and life endangering adventure.