Mike and Geoff win a prestigious award that motivates them to build a mini-tank to test against high caliber weapons. Then, the twins take the crew on a survivalist trip to test their skills and have a little fun.
The Howe twins engineer an all-terrain vehicle rugged enough to drive in coal mine tunnels. Tensions start to flare as the deadline passes and the crew feels the heat to complete the rover before the contract is canceled.
The US Army requests that the Howe twins make improvements to their most iconic tanks called Ripsaws by converting one of them into a unmanned version. But first, they show off the Ripsaws on a science-oriented television show which could mean trouble for the Army contract after the tank's tires are damaged during filming.
The Howe twins design the Mini-Rip, a smaller version of their famous Ripsaw tank which they want to debut at a motor-sports event in New Hampshire. At the same time the brothers get an order for three Subterranean Rovers and Geoff has to present the large Ripsaw to Army officials for yet another potential contract. This increased workload puts a strain on the brothers and the crew which jeopardizes all of the projects.
Geoff is focused on designing an amphibious concept vehicle which distracts him from the core business and strains his relationship with twin brother Mike. Meanwhile, the crew is overworked and behind schedule on building a fleet of Subterranean Rovers causing Mike to switch roles with Geoff to become the responsible partner.
A SWAT team requests a test of the smallest armored tank in the world called the Badger but a previous explosives trial severely damaged the vehicle. Now, the crew is under the gun to restore the Badger quickly while also completing their other orders.
The Howe brothers move their business into a new shop and add a female welder whom they task with completing a difficult job under a tight deadline. Meanwhile, the crew constructs a firefighting robotic vehicle called Thermite.
The Howe twins put their firefighting robotic vehicle through a series of tests but one trial goes haywire resulting in a costly setback. Then, Mike travels to Maryland to demonstrate the Ripsaw in front of their best client.
The Howe brothers build an all-terrain wheelchair called RipChair for a disabled veteran. Meanwhile, Mike and Geoff compete to see who can construct the best armor to protect the amphibious tank's computer system.
The Howe twins build a vehicle for a Hollywood film while the crew performs a risky underwater test on their amphibious tank prototype they are constructing for the Army.
As the contract deadline to deliver the Riptide nears the team tests the tank with disastrous consequences but Mike's turret for the vehicle is a huge success.
The crew gets into high gear to fix the amphibious tank's engine before presenting it to the Army but an important member of the team is in the hospital making the task even more difficult.