First the lights go out . . . then they die.

The body count is rising. Six murder victims. The only connection? An X carved into the dead person's chest. When the family of one of the victims asks the Artic Circle Murder Club to investigate, the team dives into their toughest case yet.

Stopping the murders isn't the team's only challenge. When Duke McAllister sees his teammate Andi Slade dodging the cops, he knows she must be in deep trouble. But Andi isn't the only one on her team on thin ice. Trouble seems to be following them all.

With more murders making the headlines, the threat level reaches an all-time high. The end game has begun. The clock is ticking, and disaster looms near. Will they stop the killer before the deadly grand finale? Or will the lights go out one final time?