Otis: True Sea Monsters

Set in 13th century Europe. A hunter is abducted and his sister is cruelly raped and killed. The hunter ends up on a trading company ship. The overseer of the cog needs someone to do his dirty work, and the hunter seeks revenge. So he has no choice but to make a deal with the overseer, in return the hunter will find out who orchestrated the event that lead to his sister's brutal death. One hand washes the other. They sail through the Atlantic and the Mediterranean, from kingdom to kingdom, port to port, the hunter is willing to do anything it takes. Through joint effort, the hunter and the overseer become cruelly efficient partners and even friends.