Iain [M.] Banks - Stonemouth

Stonemouth is a 2012 novel by Scottish author Iain Banks. The novel was published on 5 April 2012 by Little, Brown and Company and follows a man returning to a small seaport town after leaving due to a sexual scandal. The Irish Times picked the book as one of their "Books to Read in 2012".
Plot summary

Stewart Gilmour returns to Stonemouth, a fictional seaport town north of Aberdeen, for a funeral. It is five years since he ran away to London after a sexual indiscretion at a wedding. Stonemouth is controlled by two rival gangs, the Murstons and the MacAvetts, and Gilmour was engaged to a member of the former clan before he had to leave