Paul Laverty writes his fourth script with director Ken Loach for the gritty coming-of-age drama Sweet Sixteen. Set in the port city of Greenock, Scotland, local kid Liam (Martin Compston) spends his days trying to make money with his best friend, Pinball (William Ruane). When he refuses to use his imprisoned mother, Jean (Michelle Coulter), as a drug mule, his criminal stepfather, Stan (Gary McCormack), and bitter grandfather, Rab (Tommy McKee), kick him out of the house. He moves in with his levelheaded older sister, Chantelle (Annmarie Fulton), who is a single parent to toddler Callum and has no love for their mother. Liam quickly comes up with the idea to buy a trailer for himself and his mom when she gets out of prison on the day before his 16th birthday. In order to get enough money to make a down payment, he comes up with a plan to steal Stan's drug stash and sell it to local junkies. With Pinball at his side, Liam starts to develop the skills of a successful businessman and gets noticed by a group of big-time dealers. Gang leader Tony (Martin McCardie) sees his potential and makes him an offer, which leads Liam toward the life of crime that he was trying to avoid in the first place.