Charlotte Holmes's life is in peril when her brilliant deductive skills are put to the test in her most dangerous investigation yet, locked aboard a ship at sea. After feigning her own death in Cornwall to escape from Moriarty’s perilous attention, Charlotte Holmes goes into hiding. But then she receives a tempting offer: Find a dossier the crown is desperately seeking, and she might be able to go back to a normal life. Her search leads her aboard the RMS Provence. But on the night Charlotte makes her move to retrieve the dossier, in the midst of a terrifying storm in the Bay of Biscay, a brutal murder takes place on the ship. Instead of solving the crime, as she is accustomed to doing, Charlotte must take care not to be embroiled in this investigation, lest it become known to those who harbor ill intentions that Sherlock Holmes is abroad and still very much alive.

In a modern world, pirates are still wreaking havoc while working closely with terrorists as well as narco and human traffickers. Captain Thor Henrikssen, known to his crew as Cap T, is an esteemed leader who must deal with the shady characters patrolling the seas. As Cap T prepares to launch his new charter yacht, Ocean's Tempest, into the heart of a quadruple threat on the high seas, he soon realizes that he and his crew are seemingly not destined to slip quietly into the idyllic life of traveling the Caribbean. Soon they are besieged by terrorists and waterborne criminals that include Ustan Bantor, a vengeful Chechen radical. Now only time will tell if Cap T and his polished crew of warriors will win their battle to protect their guests and other seafarers from a ruthless killer determined to carry out his evil mission. In this riveting thriller, a seasoned yacht captain and his crew become embroiled in a ferocious skirmish with the shady characters lurking the high seas.