Ken Loach’s 2002 feature about a poor 15-year-old boy living in a seaside town in western Scotland is a real heartbreaker; like The Bicycle Thief and Rebel Without a Cause, it confronts the tragedy of someone trying to be a good person who finds that the world he inhabits won’t allow it. Liam (played by teenage soccer pro Martin Compston) has a mother in prison; his sister loves him but can’t understand why he gets into so many fights, just as his mother’s lover can’t understand why he refuses to slip drugs to his mother in prison. Paul Laverty’s script, which won the best screenplay prize at Cannes, never sentimentalizes Liam, yet it fully draws us into his world. I’m not prone to like socially deterministic films of this kind, yet Loach is so masterful at squeezing nuance and truth out of the form that I was completely won over. The Scottish brogue is subtitled. 106 min. Gene Siskel Film Center, Saturday, March 22, 5:30, and Monday, March 24, 6:15.