Britannic

During boarding in Southampton in 1916, Vera Campbell travels with Lady Lewis to Greece aboard the Britannic. She discloses to Captain Barrett and First Officer Townsend that she is an operative of British Intelligence and suspects a German spy is among the crew. Barrett is skeptical, while Townsend begins to warm to her.

The German spy, masquerading as Chaplain Reynolds, boards Britannic and discovers the ship secretly carries small arms and munitions bound for Cairo. He launches sabotage plans to seize or sink the liner and incites the Irish stokers to mutiny. He argues that his actions are legal under wartime articles of war.

Early in the voyage Vera reports odd sightings and suspicious behavior to Captain Barrett, who scoffs at her concerns. Townsend begins to take Vera more seriously and offers support. The tension foreshadows a hidden danger aboard Britannic.

A mutiny by the Irish stokers is foiled when Vera intervenes, killing a mutineer with the crew's help. The act earns Vera the respect of Captain Barrett and the crew, and Townsend treats her as an equal from then on.

A German U-boat tries to torpedo Britannic, but HMS Victoria intercepts and sinks the submarine. The ship sustains no lasting damage and Britannic continues its mission as a hospital ship.

Shortly after departing Naples, Reynolds makes the decision to sink Britannic as part of his sabotage plan. Vera's suspicions about his true motives begin to intensify as the voyage continues.

Vera and Reynolds share a private liaison aboard Britannic, a moment that deepens Vera's emotional stake in the mission. She later discovers his true identity and realizes she has fallen for a spy.

In the engine room, Reynolds discloses his real identity as Ernst Tilbach and confirms his allegiance as a German spy. The revelation confirms the betrayal at the center of the sabotage plot.

Following his revelation, Ernst triggers the sabotage by blowing a hole in the Britannic's bow. The ship begins to flood as it struggles toward the Greek island Kea.

Vera discovers that Lady Lewis's son William has disappeared amid the panic. Ernst helps her locate the boy and, along with crew cooperation, get him into a lifeboat before it is lowered.

Another explosion floods sections of Britannic, trapping Ernst in a flooding room. Vera fights through the chaos, helps him escape, and they move toward the exterior of the sinking ship.

They swim through flooded compartments and vents and manage to reach an open lifeboat that has been lowered into the water but remains attached by its ropes. They climb aboard and prepare for the final attempt to survive.

Ernst ties Vera to a line and, after sharing a kiss, pushes her toward safety. He remains on the lifeboat when the ropes break and it is drawn into the ship's spinning propellers, sacrificing himself as the Britannic sinks.

The Britannic capsizes and sinks beneath the waves. HMS Victoria arrives with the rescue ships to recover the survivors, and Vera is comforted by Townsend after the tragedy.