Submarine (2010)

In the Welsh seaside city of Swansea, Oliver Tate is an eccentric, unpopular 15-year-old who is infatuated with his mischievous classmate, Jordana Bevan. After Oliver bullies another female classmate to impress Jordana, she invites him to meet secretly after school, before taking pictures of her and Oliver kissing. Jordana uses the pictures to make her ex-boyfriend Mark jealous, resulting in Oliver being beaten up by Mark at school for refusing to call Jordana a "slut". Jordana becomes Oliver's girlfriend and, after a couple of weeks, they lose their virginity to each other in his bedroom while his parents are out. Oliver begins to suspect that his mother Jill is having an affair with a previous lover, New Age motivational speaker Graham Purvis, who has moved in next door with his girlfriend Kim-Lin. Worried about his parents' marriage, he monitors their sex life by checking the dimmer switch in their bedroom, concluding that they have not had sex for seven months. After spotting Jill in town with Graham and overhearing her talk about him on the phone, Oliver tries to warn his depressed father Lloyd, who dismisses his suspicions. Oliver spies on Jill attending one of Graham's seminars, where Graham tells her that he has broken up with Kim-Lin. As Oliver's relationship with Jordana grows, she reveals that her mother has been diagnosed with a life-threatening brain tumour. At an awkward early Christmas dinner at Jordana's house, Oliver is welcomed by her parents but witnesses her father break down emotionally after a dimmer switch stops working. Despite agreeing to visit Jordana's mother at the hospital the day of her operation, Oliver loses his nerve and temporarily disappears from Jordana's life so he can focus on salvaging his parents' marriage, planning to resume his relationship with Jordana afterwards. On the night of New Year's Eve, Jill goes to the beach with Graham. While searching for Jill on the crowded beach, Oliver is stunned to see Jordana with another boy. He then spies on his mother entering the back of Graham's van and assumes the worst. Enraged, he goes home and takes several of Lloyd's antidepressants before breaking into Graham's house, where he gets drunk and commits minor acts of vandalism. Upon returning home, Graham finds an intoxicated Oliver. Graham later drops Oliver off at his doorstep and leaves. The next morning, Oliver awakes to see that his parents are not angry with him and are reconciling, though Jill admits that she gave Graham a handjob. Jordana breaks up with Oliver via a letter informing him that she is seeing someone else and that her mother's operation was successful; he becomes depressed over the next few months. At school, Oliver is commonly harassed by classmate Chips. Oliver later apologises to Jordana for not visiting her mother at the hospital, hoping she will leave her new boyfriend for him, but she rejects him. Oliver later encounters Jordana on the beach at sunset, learning that she does not actually have a new boyfriend. She declares that Oliver was horrible to her, and he admits that he made a mistake. Together, they walk several inches deep into the sea, smiling at each other as the sun shines at them.