Ellen summons Paula for a dressing down but it soon becomes very personal for both of them with no going back.

Three-part psychological thriller about a woman who fears her maternity leave cover is out to steal her life.

When Ellen gets pregnant after landing a big contract for her firm of architects, she hires Paula as cover, but she soon fears she has made a terrible mistake. Ellen wants to get back to work quickly, but Paula thinks Ellen should be putting her baby at the centre of her life.

Paula wastes no time in moving in on Ellen's bosses, clients and friends, and Ellen fears she is being forced out. Everyone thinks Paula is great and Ellen is being paranoid, until a site accident puts Ellen's suspicions into overdrive.