三十五岁左右的著名建筑师Ellen（Morven Christie）怀孕了，聪明热情的Paula（Vicky McClure）将在她休产假期间顶替她的工作。Ellen很想在工作交接的过程中支持她，但有些事情感觉不对劲。Ellen怀疑自己的「代班」有不可告人的目的，令她不得不担心自己的安危。她的这种疑心究竟可信吗？是女性竞争的结果，还是升到一定级别的职业女性的「不安全感」在作祟？或者，她的感觉牵出了一些更深层的东西？

When Ellen, a successful architect in her mid-thirties, falls pregnant, she finds maternity cover in Paula: brilliant, enthusiastic and raring to go. Ellen wants to champion her, but something’s not right. Ellen begins to fear for her safety when she suspects her maternity cover has a disturbing agenda. Can her suspicions be explained away as female rivalry and her own insecurity of opting out of work at the top of her game… or do they speak to something deeper?

This chilling mini-series examines the darker side of working women, motherhood and the issues that arise from making “the right choice”.