Rossi reveals details of Annie's hidden history, leaving Tosh and Calder to wonder whether they might be dealing with something bigger and more dangerous than previously thought. Noah gives a heart-breaking account of the fateful night but falls short of identifying the killer. He does, however, give Calder a strange, cryptic detail which spikes her interest.As conspiracy theorist Angus Wallace monitors the marine research facility, the opportunity to infiltrate presents itself. When he fails to return, his friend Lisa raises her concerns to Rev Alan Calder.Meanwhile, an emotional John Harris opens up to Tosh about his fondness for Annie. However, when a new connection to Bergen is unearthed, the team quickly grow suspicious of John's sons, Patrick and Fergus. As the Harrises find themselves under the police spotlight – and John wrestles the loss of his friend Annie - their family dynamic begins to unravel with shocking consequences.