Nick is called in to rescue a squaddie who has trapped his helmet in an IED tripwire.

As the squaddie panics, Nick realises this may not be straightforward and things take a worrying turn. With the help of Bird, Towerblock has to overcome his own fears and prejudices in order to uncover exactly what happened during the operation and Simon makes a life-changing discovery.

Meanwhile, the Lt Col has arranged a base pub quiz, and sends Mac and Rocket on a wild goose chase to try and cheat their way to victory.