The Hollow Below follows Mara Bell, a newly qualified mortuary scientist who takes a position at Vale & Daughters, an old funeral home in the Somerset village of Ashby Hollow. Still grieving her younger brother Jonah, Mara is drawn into the village’s buried history when she discovers an impossible three-branched mark on the body of Evelyn Reed. The same mark later appears on Darius Cole and Nia Baptiste. Through Evelyn’s ledger, Darius’s culvert map, family letters, and old county records, Mara discovers that three labourers died during drainage works beneath the village in 1889. Their families—the Reeds, Coles, and Frys—became bound to an ancient presence beneath Ashby Hollow, while the Vale family established the funeral home above it to maintain a continual watch. As the deaths accumulate, the presence begins impersonating Jonah’s voice, exploiting Mara’s grief. Mara eventually recognises the deception and joins Luther Vale and Camille Baptiste in descending into the underground chamber. There, they learn that the entity never truly wanted death or sacrifice; it wanted to be acknowledged and remembered. The deaths occurred when generations allowed the community’s attention to lapse. Mara rejects the old cycle of sacrifice and offers instead an honest acknowledgment of Jonah’s death and her own grief. The entity accepts a new pact: each year, a living witness will return to speak plainly about what lies beneath the village. Ashby Hollow begins openly remembering its dead and teaching the truth of the pact, while Mara continues her work at the funeral home. The story ends years later with Mara noticing a possible version of the mark on her own body. She cannot determine whether it is real or merely shadow, but she chooses to keep showing up, remembering, and refusing to look away.