Ros is being held hostage in the Saudi Embassy although the terrorists aren’t aware that she’s working with MI5. The hostage-takers issue demands to the Saudi King: release al-Qaeda prisoners or one hostage will be killed every hour. Back on The Grid, the team realises that someone is feeding information to the terrorists. Suspicion falls on new girl Sally and the discovery of her dead body and the evidence planted by Neil on her computer seem to confirm their suspicions.