It's winter in Blue Lake, and Lena's wedding is weeks away. Before she can focus on the final plans with her fiancé, Sam, she must attend a much-publicized promotional event: a sleuthing competition between Camilla and three other bestselling mystery writers. The event will take place at Green Glass Manor, a mansion belonging to the wealthy Hardwick family, located just outside Blue Lake. The family estate happens to be the home of the publicist running the event, a long-time friend of Camilla's. Alexandra 'Sasha' Hardwick, a publicity guru, has dreamed up the event as a way to garner new fans for her writer friends, but also as a way to make money.

Lena and Camilla brave a blizzard to take part in Sasha's mystery challenge. Camilla knows the other writers, and feels exuberant at the thought of a reunion. But when the four famous competitors come together in Green Glass Manor, they are soon snowed in, and a brutal crime has them longing to get out.

Lena and Camilla must forget their game of make-believe to sort through genuine clues and find a real killer, knowing that someone in the house with them has committed murder. As time ticks away, they feel the growing menace in the cavernous mansion, and their suspicion of former friends begins to grow . . .