When the Light Breaks

Una sneaks out because she and Diddi are having a secret affair. When she hears Gunni (their mutual friend) coming home, she leaves quietly to avoid being seen leaving Diddi's house, as their relationship was hidden from others.

The sneaking out early scene establishes the secret nature of their relationship, which becomes central to the film's emotional conflict.

A massive fireball explodes inside an Iceland road tunnel, which becomes known as the country's worst tunnel tragedy. The disaster is shown during the opening sequence as part of a lights performance set to Jóhann Jóhannsson's Odi et Amo, and it claims Diddi's life.

The tunnel sequence appears during the opening, before the characters learn about the tragedy, creating dramatic irony.

Una resents Klara because Klara gets to be the public face of mourning Diddi as his girlfriend, while Una must hide her grief as merely a friend. Since their affair was secret, Una grieves alone for a relationship that no one else acknowledges.

Earlier scenes establish Una's secret affair with Diddi, making her resentment of Klara's public status understandable.

The film presents the tunnel disaster as a sudden, catastrophic event. There's no indication Diddi knew about the impending disaster - it appears to be a tragic accident that catches everyone off guard, including the characters who learn about it later in the day.

At the bar, Una reveals she is pansexual and mentions her last relationship was with a man. This confession comes during a conversation with Klara, who reveals Diddi had told her she was a lesbian. The exchange highlights the complexity of identity and the hidden aspects of their relationships.

After a day of shared grief, mutual confession, and tense conversations about art and identity, Una and Klara find solace in each other. The ending suggests they are forming a tentative connection through their shared loss - both loved Diddi, even if only one relationship was public.

The glass door scene earlier shows their reflections merging, foreshadowing their physical closeness at the end.

Jóhann Jóhannsson's Odi et Amo (meaning "I hate and I love") plays during the opening lights sequence that transitions to the tunnel disaster, and returns at the film's end. The piece's duality reflects the film's themes of conflicting emotions - love and loss, grief and healing, hatred and forgiveness.

The film unfolds entirely within one day - from morning to night - to concentrate on the emotional arc of processing sudden grief. This compressed timeframe intensifies the emotional experience, showing how a single day can contain shock, denial, mourning, and tentative healing.

The glass door scene shows Una and Klara standing on opposite sides of a glass door, their reflections merging together. This visually represents their growing connection despite their different relationships with Diddi - one public, one secret - and suggests they are beginning to see each other as allies in grief rather than rivals.

Diddi leaves early without explanation, which is part of the film's portrayal of their secretive relationship. The exact reason isn't stated, but it suggests Diddi needed to return to his public life with Klara, maintaining the hidden nature of his affair with Una.

This early departure establishes the pattern of secrecy that defines their relationship.

After Diddi's death, the friends attend an impromptu service at Hallgrímskirkja, Iceland's largest church. The entire country is in mourning for the tunnel disaster victims. The service provides a public space for collective grief and forces Una to mourn publicly alongside Klara, highlighting the contrast between public and private mourning.

Gunni is Diddi and Una's mutual friend at the arts college. He is the one who tells Una about the tunnel disaster and learns that Diddi may have been inside. Later, he confirms to Una that he knew about her affair with Diddi. Gunni serves as a bridge between the public and hidden aspects of Diddi's life.