Katie keeps her affair with a patient secret. Lawyer Sioghan is tired of trying to become pregnant by her husband, and is instead interested in a work colleague.

Siobhan is wracked with guilt following her passionate liaison with Dominic and confesses all to Jessica. She claims it won't happen again, but the chemistry between them is undeniable and Siobhan finds it hard to ignore.

Richard asks Trudi out to dinner, but it doesn't go to plan and they have an awkward, stilted date. Overcome by nerves, Trudi spends dinner talking about her husband, Paul. Hari and Siobhan consult a doctor regarding their inability to conceive, but are distraught to learn that Hari is infertile. Meanwhile Katie takes Sam to see an exhibition of architectural designs in an effort to convince him to return to college

After spending a passion-filled night together, Alex suggests she may cancel the wedding, but Jessica's reaction forces her to keep her plans. Katie struggles to fight her attraction to Sam, and though Trudi discovers the source of her nuisance phone calls, she is left just as confused as ever about her relationship with Richard when Sally arrives with a revelation

Siobhan hopes she can get her boss to promote Dominic to another branch. Katie tries to contact Sam, who shows up in the middle of the night. Trudi tells Richard that she wants to stay together with him.

Trudi's shocking discovery leaves her reeling while Siobhan faces a devastating dilemma.

Four friends find their lives intertwined when they are all touched by infidelity.