Brimming with excitement and hope for a fresh start, Josh and Renai Lambert move into their new home with their three children. But the couple's bliss is short-lived. When a mysterious accident leaves their young son, Dalton, in a science-defying coma for months, blood-chilling occurrences in the house can only mean one thing: something evil has set its sights on robbing the Lamberts of what they hold dear. With despair replacing happiness, experienced paranormal investigator Elise Rainier agrees to infiltrate The Further—the dark realm of lost spirits—to search for the Lamberts' missing son. However, after her life-altering experiences in Insidious: The Last Key (2018), Elise is more exposed than ever to the all-consuming darkness. As answering these questions demands courage and faith, could Dalton's shackled soul be trapped behind the ominous red-lacquered door?