Art student Una is in a secret relationship with Diddi and they dream of a future together. But before that is possible, Diddi must first end his relationship with his official girlfriend. On the way to her, the unthinkable happens: Diddi dies in a devastating tunnel fire with many victims. Una is surprised by the news at school and hours of uncertainty follow for her and Diddi's friends, while they are taken in by authorities. When it is confirmed that Diddi has also died, their world collapses. At home, the friends seek support from each other, and in a mixture of sadness, anger, disbelief and joy, they recall memories of their good friend. Meanwhile, Una struggles to find her place among this company, especially when Diddi's girlfriend Klara shows up - completely unaware of his secret relationship with Una.
When The Light Breaks shows that sadness can look different for everyone and gives space to everyone's feelings. The film was the opening film of the Un Certain Regard program of the Cannes Film Festival and has already received several awards.