Nikki Castillo

While decommissioning an old nuclear missile, an accident causes the team to endure exposure to toxic vapour while trying to prevent the nuke from detonating. Paige confronts Happy about constantly tagging along with her and Walter.

Paige's maternal side goes into high gear when an unconscious boy gets stuck in the wheel well of an airborne aeroplane; Walter's white lie to Paige starts to take a toll on him; Paige realizes something is amiss.

Team Scorpion must use their high IQs to win a softball game; Walter's secret night out with Florence puts Toby and Happy on edge.

A device that can prevent a nuclear meltdown is tracked through the Los Angeles sewers; Walter learns to listen and not offer advice to Paige; the team meets their new neighbour.

On Valentine's Day, Team Scorpion must help a doctor and pilot who are trapped inside a helicopter; Toby and Happy wait for news on their fertility results; Sylvester realizes that he may have feelings for Florence.

Team Scorpion heads to the bayou to track down a cagey alligator to stop a deadly virus; Paige teaches Walter the concept of the "white lie"; Walter hits Cabe with a tranquillizer gun, and Toby must save his life.