After Miss Jane Marple is made a trustee of a merchant marine training vessel, a fellow trustee is poisoned, and ship's officers are later murdered after she comes on board.After Miss Jane Marple is made a trustee of a merchant marine training vessel, a fellow trustee is poisoned, and ship's officers are later murdered after she comes on board.After Miss Jane Marple is made a trustee of a merchant marine training vessel, a fellow trustee is poisoned, and ship's officers are later murdered after she comes on board.