In the opening pages of The House Across the Lake, the structure is established as alternating between “Before” (presented in brief sections) and “Now” (which make up the bulk of the narrative), framing the events that led to the narrator kidnapping and tying someone to her bed. The first section introduces the reader to Lake Greene, the mysterious, dark-watered lake in Vermont surrounded by five lake houses, one of which belongs to Casey Fletcher. Having grown up playing in its water, Casey does not fear the lake, but still holds onto memories and superstitions she heard about it as a child.

The first “Now” scene finds a storm raging outside Casey’s lake house while she talks to detective Wilma Anson, who confronts her about her missing neighbor, Tom Royce. Detective Anson entreats Casey not to interfere with the investigation of Tom Royce’s wife, Katherine, anymore. However, as soon as Detective Anson has left, Casey makes her way upstairs to a spare room where she has someone tied to the bed and gagged. Removing the gag, she demands a confession from him.

Switching to “Before,” the next section explores how Casey and Katherine first became acquainted.