On Scorpion Season 4 Episode 4, Team Scorpion takes a job from the Air Force at a nuclear missile silo. They are hired to replace corroded hardware with 3D printed replacements as well as upgrading the software. Should be an easy job, especially with junior intern Cabe on the case.

Well, this is Scorpion, so something has to go wrong. Happy accidentally drops one of a 3d printed wrench, which punctures one of the fuel tanks causing a rocket fuel leak. Team Scorpion has to act quickly to stop the leak.

There are some personal issues affecting this mission. Paige is tired of Happy joining in on all of her dates with Walter, and when she confronts Happy, Happy reacts with anger, sarcasm, and hostility. This makes for a fun work environment.

While Walter is plugging the leak, he falls and is knocked unconscious, hazmat-face first into a pool of nuclear waste. It's only a matter of time before the nuclear waste corrodes Walter's suit and kills him.

Paige and Happy have to put aside their differences and work together to save Walter. But, unfortunately, Team Scorpion isn't out of the woods yet.

When the rupture re-opens and doubles in size, there's no other way to save the day than to detonate a nuke. Yup, you heard me right, Team Scorpion detonates a nuclear warhead.

The plan is to detonate a dead one, but that doesn't work out either. A live nuke is in the air, and Team Scorpion has no idea where it is going. They have 20 minutes to find it and disarm it. 

Don't worry, Taem Scorpion manages to find it in time, and Happy disarms it.

Meanwhile, Team Scorpion searches for a lawyer for Cabe. After saving the science club (again), Sly decides that he will become Cabe's lawyer.