First-time writer-director Joshua Giuliano’s slasher River became one of the Toronto International Film Festival’s biggest acquisitions, selling to Universal and Blumhouse for more than $10 million. The film follows three estranged siblings stranded on a rural river, where they are stalked by a masked killer, and its combination of family conflict, grounded characters and horror has generated significant industry interest.

River stars Jessica Rothe, Jane Levy and newcomer Max Mattern, with Dane DiLiegro playing the new killer. In an interview, the cast and Giuliano discussed developing their on-screen chemistry, filming physically demanding sequences, and creating the killer’s mask and distinctive physicality. Rothe said the film’s emotional focus on sibling relationships made the horror more affecting, while Levy was drawn to Giuliano’s fresh voice and the support of producer Nick Antosca.