Batman & Mr. Freeze: SubZero (1998)

Mr. Freeze is living in the arctic with his cryogenically-frozen wife. When a submarine destroys her containment capsule, he has to find someone to "donate" a new heart for her. His search turns up one donor with the right blood type: Barbara (Batgirl) Gordon. Her kidnapping sends Batman and Robin on a hurried chase to free her in time.—Michael "Rabbit" Hutchison