A drive-in fundraiser turns deadly when a sponsor is found murdered, and multiple suspects confess; as Alphy faces painful truths, Geordie grows jaded, Cathy clashes with Mrs. C and Leonard searches for purpose.

A Cambridge quiz team member's death turns deadly when Alphy's Bible appears at the scene. While Geordie rushes to judgment, Alphy reveals a hidden world of bullying, secrets, and shame.

Still reeling from his mother's departure, Alphy drowns his sorrows until a case at crumbling Larson Manor forces him back to work—and into a mystery.

Alphy's trip to reconcile with his mother takes a shocking turn when he meets someone and uncovers painful family truths. On the train home, a passenger is murdered and Alphy becomes the prime suspect amid prejudice and fear.

A man found dead near Bishop Grey's home leads Alphy and Geordie to uncover Church corruption. Alphy's faith wavers confronting hypocrisy while Geordie gets promoted but grows distant from Cathy. Meanwhile, Leonard returns to his calling

Cathy's triumph at CeCe's turns dark when a club manager is found dead and Alphy is discovered drunk at an illegal poker game. Geordie uncovers extortion as friendships fracture and faith falters.

As Grantchester swelters in August heat, Alphy seeks redemption while Geordie investigates crook Frank Brook's murder. Armed robbers storm CeCe's Boutique, taking Cathy and Mrs. C hostage.

After CeCe's siege, Geordie fights for his life while fugitive Dex Sutton flees. Alphy and Larry track him through Cambridgeshire as Alphy's faith crisis peaks.