Summary Frixos, a blunderer who thinks he is real Sherlock Holmes, works as a detective in a investigations agency, where, one day, he is assigned to find the niece and sole heir of a major shipowner Minas Giakoumis, who has been missing for a long time. The sole mark of identification by which he will be able to recognize her is a mole on the girl’s left buttock. With this information Frixos starts looking for the mole, upsetting the island of Kos, where suspicions indicate that the missing girl would be, without, of course, any result. However the detective from a competing agency, Paul, who has also undertaken the same assignment, manages to discover that the person they are looking for is the girl that Frixos is in love with, namely, his assistant Mary.