In the summer of 1995, two vulnerable teenage girls are accused of murdering their schoolteacher. For seventeen years, the two girls go their separate ways, Poppy having been charged with the murder. Fast-forward to modern day. Happily married mother Serena is now back in the same seaside town for the first time as she cares for her dying mother Rachel. Poppy is living in quite different circumstances. Having served seventeen years for a crime she still insists she didn’t commit, she has only one thing on her mind… the truth. And if she didn’t kill Marcus, then who did?.