[N 1][2]At "Port Amberley", a secret aviation research station somewhere in England, a group of scientists are working on the prototype of a revolutionary new aircraft, a supersonic nuclear-augmented jet aircraft code-named M7, taking off and landing on water[N 2] and capable of flying at up to 2,000 miles per hour.

The project leader Michael Heathley (James Donald) is so wrapped up with the M7 that his wife Lydia (Phyllis Calvert) feels neglected and that she is being sidelined in favour of her husband's work.

At a social gathering, she strikes up a conversation with Michael's colleague Alex Leon (Herbert Lom), and the pair are soon circling one another.

Meanwhile, the project's security members strongly suspect there is a spy in their midst and deploy agents to follow the scientists when away from the station.

"The Net is essentially a thriller owing a great deal to contemporary Cold War tensions, but interestingly, it still pays homage to the notion of progress and utopianism through aviation and suggests that Britain is in the forefront of space research.