In celebration of Adam's birthday, Marion, Thomas and Christine arrive at an island lodge off the coast. Here they party, swim in the ocean and reminisce over old times. Everything a getaway should be. But when the idyllic holiday is shattered by a masked man that viciously attacks and imprisons them, the friends realise their fragile lives are in mortal danger...

Beaten, bleeding and exhausted, the friends struggle to come to terms with the Intruder's revelation: Is one of them capable of murder? Driven by ruthless efficiency, the Intruder subjects each of them to deadly interrogations to coerce a confession. But as doubts arise from the Intruder's motive and the events of a stormy night in their past, the friends are forced to work together to survive.

Consumed by despair, Marion dashes for freedom while Christine and Thomas are imprisoned in the lodge. As the Intruder hunts Marion across the island, Christine and Thomas try to plot their escape. But as the violent events of the night unravel, they realise something more insidious is happening.

During a birthday getaway on a secluded island lodge, four best friends and university graduates -- Adam (Benjamin Kheng), Thomas (Edwin Goh), Marion (Naomi Yeo) and Christine (Eugena Bey) -- unwind to have fun, contemplate their futures, and forget about the harsh realities of adulthood. But when their party is interrupted by a masked Intruder (James Kumar), they are viciously trapped and subjected to a series of brutal interrogations...