Part 1 in this serial about Hitler's secret weapon against Britain.

A special team has to be selected for the operation.

The selected recruits are to meet at a designated rendezvous.

As the training continues, they emerge as individuals.

Parachute training begins, and there is suspicion there might be a secret agent.

The team may have found a way into the V1 storage dump.

The team are employed into a real operation in France but Portales loyality is in question.

Major Gallagher discovers a way to cross the minefield which surrounds the German bomb dump.

The deadline for the official selection of the team approaches but tempers flares and quarrels begin.

The team is given a detailed briefing for the attack on the bomb dump but one of team opts out and the operation faces failure.

The team has been briefed and they all recognise the importance of their mission and that their chances of survival are limited.

Gallagher and his team have gained access to the German underground but their entry has been discovered.