Gabriel (Dermot Murphy), a drummer with bipolar disorder, plays with the up-and-coming rock band Flood Tides. Due to his increasingly extreme and erratic behavior, his psychiatrist Dr. Flavahan (Annie Ryan) has put him on medication and ordered him to join a mixed-ability football team to help him deal with the side effects. There he meets Christopher (Jacob McCarthy), a seventeen-year-old goalkeeper with Asperger's who has spent the last five years in an institution. Christopher follows Gabriel to a gig, where he turns out to be startlingly good at packing gear, and Flood Tides hire him as a roadie. Christopher and Gabriel form a genuine friendship, but Gabriel's mental illness threatens to destroy everything he's worked for.
The Drummer and the Keeper contains examples of:
- As Himself: The Strypes, another band, appear as themselves towards the end of the movie.
- Broken Treasure: During Gabriel's final manic episode, he breaks into Christopher's institution and sets his beloved LEGO mansion on fire, causing Christopher to suffer a Heroic BSoD. During Gabriel's ensuing months of institutionalization, he spends part of his trust fund on LEGO sets so he can rebuild Christopher's mansion, then has it sent to him as part of his efforts to make amends to everyone he hurt during his episode.
- Disappeared Dad: Christopher's dad left when he was three. Now he lives in another country, so they don't see each other.
- Driven to Suicide: Gabriel's mother had bipolar disorder, too. She committed suicide via paracetamol overdose. She lingered for four days.
- Groupie: Christopher gets his first blowjob from the groupie Jamie (Jane Herbert). Gabriel warns Christopher that Jamie is attracted to bands, not people, and won't be there for him when he needs her, but Christopher tells him off for insulting his potential girlfriend.
- Hates Being Touched: Christopher is very protective of his personal space. His first interaction with Gabriel involves being upset because Gabriel broke the rules of football by shoving him.
- Let Me Get This Straight...: This is Christopher's stepdad Jeremy's reaction to Christopher's plan to have Gabriel released into his care, allowing both of them to live together outside of an institution.
- No Medication for Me: When Gabriel finds out that Flood Tides are replacing him despite his efforts to get his life back under control because his drumming hasn't been as good since he went on medication, he flushes all his medication down the sink and spends the night drumming. The ensuing manic episode is so disastrous that he spends the next two months in a mental hospital, with nobody willing to visit him except his psychiatrist.
- Parental Abandonment: Christopher's mother and his stepfather Jeremy have told him that he can move back in with them when he's eighteen. In fact, they don't want him at all and plan to transfer him to another institution for adults. They don't bother to tell Christopher about their plans, leaving him wondering why he's still institutionalized weeks after his eighteenth birthday.
- Pyromaniac: Gabriel likes to light things on fire during his manic episodes. It can be anything from a match to a van.
- Security Blanket: Ciara (Hannah Mamalis), a girl who spends all her time in the music room in Christopher's institution, spends every scene tightly wrapped in the same blanket.
- Self-Immolation: Gabriel finishes his final manic episode by setting himself on fire in front of what he thinks is the house of pop star Nevo, who he believes has been coming to his gigs. At the hospital afterwards, he learns that he didn't even have the right address.
- Special Thanks: "With very special thanks to the Strypes."
- Staging an Intervention: Gabriel's sister Alice (Aoibhinn McGinnity) and his bandmates Pearse (Charlie Kelly) and Toss (Peter Coonan) have him meet them in the rehearsal room, where they inform him that he'll be fired from the band if he can't get his act together.
