The Tunnel

A group of wealthy industrialists gathers at Mr. Lloyd's home as Lloyd introduces Richard 'Mack' McAllan, the engineer behind the Channel Tunnel. McAllan explains the concept of Allanite steel and a radium drill capable of crossing the Atlantic. The moment sets the stage for major financial and political commitments to the project.

Lloyd's backing and Mostyn persuade the group to buy shares in the project. The investors are skeptical at first, but the promise of future unity and economic prestige convinces them. The team begins shaping the financing and corporate control of the venture.

Mack's success as the lead engineer makes him a worldwide celebrity, yet his fame pulls him away from his wife Ruth and their young son Geoffrey. The project’s profile rises even as personal strains emerge, testing loyalty and focus. Public attention helps fund-raising, but the personal costs are high.

Mack travels to New York when summoned to reassure the public and political leaders. He learns that popular support for the tunnel is slipping and that continued celebrity backing might be necessary. Lloyd urges him to use his fame to mobilize backing and keep the project alive.

Lloyd's daughter Varlia, secretly in love with Mack, keeps him company during public appearances to heighten media interest. Her presence adds romantic intrigue and press attention to the project. This dynamic complicates Mack's personal life and the public narrative around the venture.

Ruth, isolated by her husband's absence, takes a job as a nurse at the tunnel site. She is exposed to an unknown gas that blinds her, a turning point that deepens the rift in Mack's life. Her loss of eyesight marks a personal tragedy within the larger project.

Believing Mack no longer loves her and fearing pity, Ruth leaves, taking their son Geoffrey with her. The separation devastates Mack and further strains Robbins and the project. The family fracture shadows the subsequent years of construction.

Despite mounting costs in lives and money, leaders in Britain and the United States press for completion, promising unity and peace. Ruth lives in the countryside with Geoffrey, who grows up and becomes involved in the tunnel project. Robbins is urged to find him a role in the enterprise.

As the tunnel nears completion, a submarine volcano forces a detour. McAllan needs more money to continue, while Grellier the arms dealer and Mostyn resist. Lloyd grows suspicious of a stock manipulation scheme designed to seize control of the venture.

Varlia convinces Mostyn to fund the continued construction by offering him marriage, a personal pledge that would fulfill his long-held wish. The plan temporarily resurrects support for the project and steadies the financing.

Grellier murders Mostyn for backing out of the settlement, tightening his grip on the company. The power struggle intensifies as investors jockey for control, threatening the tunnel's fate. Lloyd's suspicions about the true financiers deepen.

Samples show the volcano cannot be circumvented, and the drill breaks through to deadly volcanic gases that kill hundreds of workers, including Geoffrey. The tragedy underscores the lethal risks of the project and threatens to derail the entire venture. McAllan's resolve is tested as the pace of progress stalls.

Ruth reappears at the tunnel site after Geoffrey's death, offering personal motivation to McAllan. Her return reinforces his determination to finish what they started. He vows to see the project through despite the human and financial toll.

With renewed determination, McAllan and Robbins recruit three volunteers to operate the radium drill under extreme conditions. They endure near-fatal temperatures as they push toward the final breakthrough. The team remains focused on bridging the Atlantic despite the odds.

The crew breaks through and reaches the American side of the tunnel, completing the England–America link. Political leaders celebrate as the long dream becomes reality. The project stands as a monument to perseverance under pressure.