Martin Sharp, portrayed by Pierce Brosnan, is on the brink of ending his life on New Year's Eve atop the Toppers Building, overlooking the bustling streets of London. On the surface, he appears to have it all: a loving wife, two kids, three dogs, and four People's Choice Awards, not to mention a prime spot on Britain's most successful morning TV show. However, a brief affair with Suzy Jenkins, a girl he met at a men's moisturizer launch who turned out to be underage, led to dire consequences—prison, divorce, and the loss of his job. Left feeling hopeless and despondent, he sees no way out but to take his own life.
As fate would have it, he is interrupted by Maureen, played by Toni Collette, who shares his dark intentions. Just as they exchange their silent agreement for a shared fate, two more strangers join them: Jess, a young woman played by Imogen Poots, and J.J., a pizza deliverer portrayed by Aaron Paul. Their initial plans for a tragic end are thwarted when rain forces Martin to retreat from the rooftop.
On his way home, he encounters Maureen at the bus stop, Jess wandering in the rain, and J.J. trying to fix his moped. One after another, he decides to help them out. Jess struggles with addiction and finds herself trapped in a dysfunctional relationship with Chaz, a user who exploits her vulnerabilities. To make matters worse, Jess is the daughter of the shadow education secretary, politician minister Crichton, leading to a strained family dynamic. Meanwhile, Maureen is devoted to her disabled son Matty but has little else in her life.
J.J., an American with a checkered past as a musician, claims to have terminal brain cancer, piling on yet another layer of despair to their assembly of lost souls. After dropping Jess off to confront Chaz, Martin and Maureen soon realize departing from her alone wasn't wise, prompting them to return and seek her out. To their dismay, they find her in the back of an ambulance, where she insists her overmedication was accidental, not an attempted overdose.
In a moment of solidarity, the four strangers form a pact to postpone their suicide plans until Valentine's Day. This agreement quickly becomes fodder for the tabloids, causing embarrassment for Jess's father and drawing unwanted public attention, especially since Jess's sister, Jeniffer, has been missing for two years. Under growing pressure, they gather at Maureen’s house, where the once somber atmosphere begins to shift.
Seizing an opportunity for financial gain from their misfortunes, Martin concocts a whimsical plan, claiming they were interrupted during their suicide attempt by a vision of an angel resembling Matt Damon. As people are drawn to their story, they appear on Martin's former TV chat show, where his old co-host, Penny (played by Rosamund Pike), adds fuel to the fire with her scathing comments. Tensions rise, especially when JJ confesses to Jess that his cancer claims were false, a revelation that adds complexity to their already complicated relationships.
After a trip to a low-budget resort away from the prying eyes of London, the group grows closer, albeit with tensions simmering beneath the surface. Maureen, experiencing air travel for the first time, embraces the perceived luxury of the hotel, while JJ's flirtation with a reporter named Kathy complicates matters further—igniting jealousy in Jess and ultimately leading to explosive confrontations among the group.
In a shocking turn, tragedy strikes when Maureen's son Matty suffers a heart attack, though he makes a recovery. Later, Jess and Martin visit Maureen in the hospital, only to realize their pact has come to an end as Valentine's Day arrives. The story culminates back on the same rooftop, where they confront J.J., unanimously coaxing him back from the edge and offering him hope.
Fast forward to New Year’s Eve of the following year, they reconnect through a video call—Martin is caring for his daughter, Maureen revels at a New Year's party, and Jess and J.J. bask in the joy of their newfound relationship, illustrating how life continues even after the darkest moments.
