In a small British town flanked by woods, May Day has started. The bunting is up, the floats are ready and the community gathers to celebrate 'new life' with a parade on the high street. But when the May Queen, 14-year-old Hattie Sutton, disappears, the news sends shock waves through the town. Soon, four residents are faced with the horrifying realisation that they suspect someone they love of taking her. As the vigilantes gather, the question is: who was Hattie really, and why would someone want to hurt her?

It is the day after Hattie's disappearance, and the town unites to search for her. Keen to win favour with Hattie's family, Steve insists on leading the lynch mob, but what is he trying to divert attention from? Could it have something to do with a visit to Seth's flat? Fiona makes a chilling discovery when she ignores Alan's protests and launches herself into some unofficial policing. Meanwhile, Linus continues his quest to find out who his father really is and pursue Hattie's twin, Caitlin. Gail calls on her son's help to invade Malcolm's privacy when he refuses to come home.

Tragedy strikes, throwing the spotlight on a key suspect and forcing Gail to face the truth of who her husband is. Meanwhile, Linus and Caitlin's relationship deepens and Everett's taste in women gives Fiona cause for suspicion. Seth's 'other side' takes him to a place that leaves him wondering if he can trust Steve. And as Alan's inquest looms, he and Fiona struggle to deal with the accusation of assault leveled against him, as well as an increasingly disturbed Charlotte.

As news of a sighting ripples through the town, Linus discovers the true nature of Everett's connection to Hattie. Fiona and Alan come to blows over Charlotte's odd behaviour and, when Alan finds himself back on the beat, a horrible discovery leaves them reeling. Caitlin is hit by a terrible blow, inspiring Linus to make a dangerous promise to her. Meanwhile, Gail and James disagree about how best to serve Malcolm's memory and Seth decides to sacrifice everything to the truth, pushing Steve to take an extreme risk.

As the town gathers for Hattie's memorial, things take a dark turn and a chaotic interruption has fatal consequences. Steve finally gets his moment with his ex, Angie - will he manage to win his family back? Fiona must face her old colleagues in a way she never thought she would, while Gail frees herself of her old trappings. Meanwhile, Everett and Linus have a confrontation which takes their relationship to a new place and, as Caitlin makes an eerie transformation, Linus realises he has made a big mistake.