In 2019, nine years after the traumatic events involving possession, Josh Lambert has struggled to repress his memories of his experience in The Further. He is now divorced from his wife Renai Lambert, and the recent loss of his mother, Lorraine, has only added to his emotional turmoil. His strained relationship with his son Dalton Lambert hits a climax when he attempts to reconnect while dropping Dalton off at college. However, their conversation devolves into an argument, leaving both feeling frustrated.
Upon starting his first art class, Dalton inadvertently sketches a picture of the ominous red door that serves as the threshold to The Further. As life unfolds around him, Josh begins to be haunted by the spirit of a man he eventually identifies as his father, Ben Burton. Believing that his father abandoned the family during his childhood, Josh faces a haunting revelation. Meanwhile, Dalton, new to college life, attends a frat party with his roommate Chris Winslow and encounters the ghost of a student suffering from an unending sickness.
After a fateful incident leads Dalton to accidentally astral project into The Further again, Chris discovers a YouTube video by Specs and Tucker that offers insight into astral projection and features Elise Rainier, who shares knowledge about the other realm. Inspired by what he learns, Dalton attempts to explore this skill once more while Chris stands guard over his physical body. However, chaos ensues when Chris becomes the target of a malevolent unseen force. Hearing her screams, Dalton rushes back to his body only to confront a horrific sight: the very red-faced demon that haunted him during his childhood.
Despite Chris's cautions to abandon further attempts at astral projection, Dalton receives an alarming phone call from his brother Foster Lambert, who recounts a recurring nightmare involving their father trying to harm them. This revelation triggers Dalton’s buried memories, prompting him to complete a troubling painting that vividly depicts a possessed Josh standing before the infamous red door. In a gripping moment, Dalton gets pulled back into The Further, facing the traumatic memory of a possessed Josh attacking them in their basement.
Meanwhile, Josh delves into the unsettling history of his father, learning that he took his own life while confined in a mental institution. In conversation with Renai, the unsettling truth about their family's past resurfaces, revealing that Josh's father also wielded the ability to astral project but mistook the horrific visions for signs of insanity. Realizing the danger Dalton is in after Foster shares a photograph of his ominous painting, Renai assists Josh in revisiting The Further to rescue their son.
With Dalton ensnared in the demon’s lair, the entity takes control of his body, ready to endanger Chris. Fortunately, Josh arrives in the nick of time to free Dalton from the clutches of evil. The chase culminates at the red door, where Josh sacrifices himself to keep it sealed, allowing Dalton to escape safely. As Dalton returns to his body, he covers his disturbing painting of the red door with black paint, effectively sealing the door to The Further.
In a moment of catharsis, Josh encounters his father's spirit, who leads him back to the realm of the living. Back among his family, he tentatively agrees to join Renai and the children for dinner, suggesting the possibility of rebuilding their lives together. As he exits, he unknowingly crosses paths with Elise’s spirit, who offers him words of encouragement about the future. In a heartfelt reunion at Dalton’s college, father and son reconcile as Dalton shares a touching painting that captures the essence of Josh carrying a younger version of himself out of The Further.
In a chilling post-credits scene, the light over the now-sealed door flickers ominously back to life, suggesting that the darkness may not be entirely vanquished.
