Five years ago, police agent Martin Schwarz’s wife and son disappeared without a trace while traveling on the cruise liner “Sultan of the Seas.” Back then, the cruise company insisted it was suicide. But Martin didn’t believe it. Then, one day, a passenger from that very ship calls him and says he must immediately come aboard the “Sultan of the Seas”—she has proof that his wife didn’t throw herself into the sea of her own will. Moreover, his son may still be alive, and strange things are happening on the liner. Leaving everything behind, Martin embarks on an unwanted journey, determined to uncover the truth…