Titanic has three different storylines. Mrs. Isabella Paradine is traveling on the Titanic to join her husband. On the Titanic, she meets Wynn Park, her former lover. She falls in love with him again, sending her husband a telegram saying that they can't be together anymore. When the ship starts sinking, Isabella must reluctantly leave Wynn.
    Also in first class is the Allison family, a real family who traveled on the Titanic, returning home to Montreal with their two small children and new nurse, Alice Cleaver. They notice something wrong with her; a maid asks her if she had been in Cairo the previous month but soon realizes that she remembers her from the highly-publicized trial where Alice was accused of throwing her baby off a train. When the Titanic starts sinking, Alice Cleaver panics and quickly boards a lifeboat with Trevor, the Allisons' infant son. The parents are unaware that the baby is safe and refuse to leave without him, which in the end costs them their lives.
    In third class, Jamie Pierce steals a ticket to get on board. He manages to become friends with the ship's purser Simon Doonan, who is a robber. Jamie falls in love with Åse Ludvigsen and they spend time on board together. However, Åse is raped by Doonan and is no longer able to trust anyone. When the ship hits the iceberg, Jamie cannot convince Åse to get into a lifeboat, but in the end she does.