When Sam returns to work a year later, she knows she is stepping back into the lion's den. After surviving the attempt on her life, Sam has now returned to discover who ordered her death. Utterly paranoid, Sam suspects everyone - including her boss, Rupert Keel, as well as her other team mates: Zoe Morgan, Deacon Crane, Hasan Moussa, and even newcomer Ian Fowkes. However, at the centre of her suspicions is Aidan.

At first reluctant to take her back, Keel is persuaded by Crane that they need her. But this doesn't stop Keel from trying to find out what really happened to Sam, something she isn't about to reveal. Neither is she about to tell Keel that the only reason she has returned is to pursue her own agenda. The only way she can find out who tried to kill her is to draw fire to herself once again.

As the team begins a new operation, working for a secret client, Sam is tasked with infiltrating the world of Jack Turner, a criminal turned multi-millionaire. She is to seduce his son, Stephen Turner, but the operation takes an unexpected turn when Stephen, seeing how well she bonds with his lonely, motherless son Edward, asks her to move into the house and work as his tutor/nanny.

Reluctant at first, Sam is persuaded to enter the house. Once inside, she is able to plant 'video eyes' cameras which the rest of the team can monitor from a nearby surveillance post. On her first night at the Turner house, Sam is introduced to Dr Horst Goebel, a water expert who is delivering a black case to Jack Turner. However, Dr Goebel isn't all that he claims to be.