The game opens with a flashback sequence showing Tyler's confession to the murder of his mother, Mary-Ann, in
self-defense as a child in 2005. Ten years later, an adult Tyler leaves the
juvenile detention center he was sentenced to and reunites with Alyson, who has been adopted by Eddy, the investigating officer of the incident. Intending to move on with their lives, the twins return to Delos Crossing to sell their childhood home, but finds the house in a state of disrepair despite the efforts of Mary-Ann's friend Sam, who had turned to
alcoholism since her death. The twins recall memories of their childhood while exploring the house, particularly
fairy tales about a runaway princess and her two goblin companions told by their mother, who compiled these stories into an illustrated journal called the "Book of Goblins". After learning about Tessa's discussions with Mary-Ann about Tyler's gender identity, the twins visit Tessa at her store, where they were told that Mary-Ann's behavior became increasingly erratic shortly before her death. The twins later speak to Eddy at the Delos police station, but he declines their request to see her file. Alyson later experiences a flashback where she stabbed Mary-Ann with a pair of scissors, and begins to suffer from
post-traumatic stress. The next morning, the twins break into the police archive and uncover files about Mary-Ann. After discovering their break-in, Eddy admits he had visited Mary-Ann to warn her on Tessa's instigation. The twins confront Tessa, who justified her actions and claimed that Mary-Ann isolated herself from the wider community, and that her alleged mental instability and parental incompetence was endangering her children. The twins return to the house to find the adjacent
barn ablaze and an arsonist fleeing from the scene. After putting out the fire, the twins realized that the arsonist had tried to access a compartment beneath the barn floor containing a locked box, inside which they find letters from someone instructing Mary-Ann to get an abortion. The twins later experience a recollection of Mary-Ann arguing with an unseen man on a boat, and that Alyson was the one who stabbed their mother. The twins briefly go their separate ways following a disagreement. Consumed with guilt and
anxiety over Mary-Ann's death, Alyson's mental health deteriorates, leading to a severe
panic attack. After she recovers, Alyson visits Sam to ask him about their potential familial ties, but discovers instead that an old photograph in his possession reveals a hidden loft above the barn. The twins regroup to investigate the loft and find a room of complex puzzles, which they solve using the Book of Goblins. They discover that Mary-Ann's fairy tales were actually metaphors for her troubled past: born to an overbearing family, she fell pregnant and fled to Delos Crossing to raise her baby, a son named Leo, who did not survive. The twins find a picture of their late half-sibling, along with a letter from Mary-Ann which is addressed to them. The twins realize that Mary-Ann had suffered a
mental breakdown over her fear of social services taking away her surviving children. The twins deduce that the unknown man on the boat, and their biological father, was in fact Tom Vecchi, Tessa's husband. After the twins confront Tom, the player as Alyson must decide whether she believes that Mary-Ann planned to
kill herself and her two children, or that she had planned to
kill only herself when Tyler interrupted her as alleged by Tom. Depending on Alyson's choices, two main concluding scenarios are presented: • If Alyson chose to admit to Eddy that she killed Mary-Ann and/or took Tom's memory of her mother's death, Tyler returns to the house one last time, with Alyson in Juneau and receiving therapy. • If Alyson never told Eddy that she was responsible for Mary-Ann's death and she believes that she saved Tyler from their mother, Alyson opts not to sell the house and moves in by herself and writes a new chapter in The Book of Goblins. Many details of the epilogue are also determined by the player's previous choices: for example, whether they make peace with Eddy and/or Tessa, or whether the twins kept their telepathic bond and a close relationship all alter the ending. == Development and release ==