Avery reflects on Vincent Blake’s belief that his son is dead and that Tobias Hawthorne hid the body at Hawthorne House. The Blake family seal, Toby’s theft of it, and Toby’s hidden copy of William Blake’s “A Poison Tree” now seem like signs that Toby wanted Tobias to know Toby had uncovered a buried truth.

Avery reconsiders Will Blake’s relationship with sixteen-year-old Mallory Laughlin and concludes that Tobias would have seen Will as a dangerous adult exploiting a girl under his protection. In Toby’s old wing, Avery rereads the invisible-ink diary and the poem Toby left behind, realizing that Toby’s anger may have come from knowing why his adoption was secret and how the Blake family was connected to him.

The line about stolen evidence being in “the darkest hole” leads Avery to wonder whether Toby found more than the seal—possibly human remains. Because Eve has not found the proof and Blake has now assigned Avery the task, Avery reasons that the body or evidence is still hidden somewhere in or around the estate.

Avery shifts from asking where Tobias would hide a body to asking when he would have done it. Since Will disappeared before Oren worked for Tobias and before Hawthorne House became its labyrinthine self, Avery studies the estate’s additions using the blueprints Mr. Laughlin gave her.

Working through the night, Avery arranges the blueprints chronologically and narrows her search to additions built around Toby’s birth. The year before Toby was born, Tobias built the greenhouse; the year Toby was born, Tobias built the chapel. Remembering Nan’s remark that Tobias threatened to build her a mausoleum, Avery suspects the chapel may conceal the answer.