As the trial of local teen Gary Bell approaches, Sidney and Geordie find themselves at loggerheads regarding his guilt – not even building a go-kart together can get them to see eye to eye. Sidney's mind is taken off these matters when he finds the anxious Reggie Lawson [Paul Nicholls] at the graveside of his dead wife, Anna. Convinced that she still haunts his home and stable yards following her suicide he implores Sidney to come to his estate, Kingsbrook and perform an exorcism for him.

Believing this to be a husband's desperate grief, Sidney goes with Reggie to investigate his claims. There he meets Reggie's new wife Kitty [Eliza Hope Bennett], their housekeeper Mrs. Elton [Jenny Ogilvie] and Anna's brother, Laszlo Herzl [Elliot Levey]. With Anna's signature perfume still hanging in the air, a painting falling from the wall of its own accord and a horse fatally kicking out after being spooked, Reggie's fears seem to have some foundation, although Kitty is quick to point out their coincidental nature. After offering prayers and council, Sidney leaves hoping that his words have given Reggie some solace. But that night, Geordie summons Sidney back to Kingsbrook: Reggie has hanged himself in the exact same spot as Anna died.

Meanwhile, the Redmond's and Sidney's parishoners are unhappy when Sidney stands as a witness for the defence in Gary's case. Are his principles going to cost him his flock? With Sidney's sister Jen [Fiona Button] throwing a party in London, it's a chance for Sidney to escape and take Margaret out on his arm. But when Amanda shows up with Guy [Tom Austen], it's clear that his own feelings are still conflicted.

At least investigating Reggie's death gives Sidney and Geordie a shared goal again. Why would Reggie take his life when his finest horse is set to triumph at the next race? And with an almost identical suicide to his late wife, why are some of the key details different? But is one shared case enough to get these best friends back on track - especially after Sidney takes the stand? Whatever the outcome of the trial - and the case - Sidney seems set on a course of action that threatens his friendship with Geordie...

Sidney Chambers has given up. Following the difficult events of the past few weeks, he is drinking like never before, and even worse, seems to have entirely stopped caring about his responsibilities as a clergyman. With Mrs Maguire and Leonard both deeply worried about him, it is left to them to try and find a way to help their friend before it is too late. But with Geordie and Amanda seemingly unwilling to help, and with an attempt to remove Sidney from the vicarage seemingly gathering strength, things are not looking good.

However, when old friend Reverend Sam Milburn returns to the parish, Sidney is thrown into even greater emotional turmoil. Claiming to be seeking forgiveness for his crimes, Sam's return leaves Sidney torn. Is Sam really here to seek forgiveness? And is it even within Sidney's gift to forgive him for crimes committed against others? Matters are complicated further when Harding and Agatha discover that Sam has returned to the village. With Harding making threats against his life, Sam flees. But when evidence of a struggle is later found, Sidney fears the worst may have happened – could Harding have murdered Sam?

Meanwhile, as Leonard continues to wrestle with his feelings for Daniel, he also struggles to make sense of a life-changing proposal from the Archdeacon. And a visit from Mrs Maguire leads to Amanda having a heart to heart with Guy.

With Sam missing, Sidney and Geordie are forced, once again, to investigate a crime together. However, when they uncover a dark secret about Sam, Sidney's fragile emotional state is pushed even further, putting even greater strain on the investigation. With tensions between the two of them at an all-time high, will they be able to put their differences to one side for long enough to stop a murder being committed?