As the clock ticks down to zero hour, Luke and the crew must break into a top-secret facility before their adversary turns off the lights — for good.

Every second counts as the team scrambles by land, air and sea to avert a catastrophe. Aldon finds himself outnumbered — but not outmatched.

Emma and Luke catch a buzz in a deep-sea submersible. Back on land, bullets and breadsticks fly in a confrontation at a pizza joint.

Barry hitches a ride to the final frontier. As an operative's cover story begins to crumble, Luke and Emma seek help from an unexpected ally.

While Cress tightens the screws, Chips matches wits with an interrogation expert. A stealth mission makes a bigger bang than expected.

As Greta attempts to loosen Luke's lips, the safe-house gang gets an earful from afar. Emma turns heads on the dance floor with an unlikely date.

A face from the past threatens Luke and Tally's recharged romance. The team breaches a fortified compound to keep vital intel out of enemy hands.

It's a sink-or-swim mission when Luke and the team dive into deadly waters to stop a sinister terrorist from making a massive splash.