Reunited in paradise but burdened by guilt—Sienna and Rusty’s second chance at love could be their last. When nerdy cyber security specialist Sienna Blackwood seeks refuge on Hawaii’s Big Island, her morning jog with her little dog turns into a desperate fight for survival when she stumbles on a murder cover-up near an ancient lava tube. Fleeing the scene, she bursts into the police station and crashes into a hauntingly familiar stranger who offers her help. Ex-Delta Force operative Russell "Rusty" Callahan thought he’d seen it all. But protecting Sienna from a hail of bullets and vanishing evidence pushes his...

Reunited in paradise but burdened by guilt—Sienna and Rusty’s second chance at love could be their last. When nerdy cyber security specialist Sienna Blackwood seeks refuge on Hawaii’s Big Island, her morning jog with her little dog turns into a desperate fight for survival when she stumbles on a murder cover-up near an ancient lava tube. Fleeing the scene, she bursts into the police station and crashes into a hauntingly familiar stranger who offers her help. Ex-Delta Force operative Russell "Rusty" Callahan thought he’d seen it all. But protecting Sienna from a hail of bullets and vanishing evidence pushes his elite combat skills, and those of his highly-trained K9, Soda, to the limit. Deep in a labyrinth of underground lava tubes, they discover a secret door leading to horrors beyond their worst nightmares. While paradise gleams above, a deadly underworld preys on the innocent below, forcing Sienna and Rusty into a desperate battle against ruthless gunmen—and the demons haunting their past. Will they save the exploited victims? Or will their second chance at love end before it begins?