The Power Couple by Alex Berenson

Rebecca and Brian Unsworth appear to have it all. A nice house in the suburbs of Washington, DC. Two well-behaved, healthy teenage children. Important government jobs—Rebecca working in counterterrorism for the Federal Bureau of Investigation, Brian serving as a coder for the National Security Agency. Their lives stand to improve even more as Brian, in his off-hours, has just developed and sold a highly profitable app.

However, the Unsworths’ marriage isn’t as perfect as it seems. After two decades together, they’ve drifted apart, talking little and having sex even less. Seeking to revive their strained relationship, they decide for their twentieth wedding anniversary to take their two kids, Kira and Tony, on a European getaway.

They have a blast…until one night in Barcelona when Kira doesn’t come home from a dance club. She’s gone. Abducted. Over the course of a single weekend, the Unsworths will do everything possible to find her—as Kira herself discovers just how far she’ll go to break free of the trap that’s been set for her. And even as Rebecca and Brian come together for Kira, they realize their marriage is more tenuous than they realized.