Claude Opus 4.8 vs GPT-5.6 Sol for book writing

The letters shouldn't exist.

They arrive addressed to Edith Brand's sister — dead for forty years — postmarked from a village that no longer exists, drowned beneath a reservoir since 1971.

Retired and haunted, Edith returns to the place she once called home, renting a room above the pub from a landlord whose memory runs deeper than the water. But the further she wades into the past, the murkier her sister's death becomes. Was it an accident? A tragedy of her own making? Or something darker, long buried?

Some secrets don't stay drowned.

And…

Retired lighthouse keeper Edith Brand has spent forty years trying to forget her sister’s death. Then the letters begin—addressed to the dead woman and postmarked from the village where they grew up, a place drowned beneath a reservoir in 1971.

Drawn back to the water’s edge, Edith rents a room above the local pub, where the landlord remembers more than he admits. As long-buried secrets surface, she must confront a chilling possibility: her sister’s death was no accident—and someone has been waiting decades for Edith to uncover the truth.