Unassuming bank clerk Gideon Prendergast just wants to prove himself at work. When his boss offers him a promotion if he can solve the five-year-old murder of Callum Monserrat, in the woodland community of Dunmurry, Gideon jumps at the opportunity. But when another victim turns up dead shortly after Gideon's arrival, he starts to wonder what kind of secrets this small community is hiding and why the bank has a vested interest in them.