The psychological horror thriller marks the feature directorial debut of Russell Goldman, expanding on his 2022 short Return to Sender, which he later adapted into a 2023 Black List–recognized screenplay. If the premise sounds simple, the descent is anything but.

In Sender, a woman’s life begins to fracture after she receives a string of unsolicited packages—each one containing eerily specific items that suggest she’s being watched. As the deliveries escalate, so does her paranoia, pulling her into a disturbing rabbit hole as she hunts for the identity of her unseen tormentor.

Lower leads the cast alongside horror royalty Jamie Lee Curtis, with an ensemble that includes Rhea Seehorn (Pluribus), Anna Baryshnikov (Love Lies Bleeding), David Dastmalchian (Late Night with the Devil), Utkarsh Ambudkar (Ghosts), Mike Mitchell (Twisted Metal), Edward Torres (Return to Sender), Alyssa Limperis (What We Do in the Shadows), and Inger Stratton.

Curtis also produces through Comet Pictures, joined by Molly Hallam and Jake Katofsky. The project continues Curtis’ mission to champion emerging genre filmmakers, something she’s been vocal about since backing Goldman’s early work.

“I am so proud to be a part of Russell’s first movie, the first of many,” Curtis said previously. “The little seed that Comet Pictures planted has now grown into a feature filled with talented artists surrounding a new and exciting filmmaker.”

Curtis and Goldman have already collaborated once before, co-writing the eco-horror project Mother Nature, which Curtis is attached to direct for Blumhouse.

Sender is set to make its world premiere at SXSW in Austin, Texas this March—where paranoia, packages, and psychological terror are officially marked “return to sender.”