After Zoe set off the fire alarm during an IQ test at school, she is forced by her father to do community service at a retirement home. Here she gets assigned to a woman in a wheelchair called Eugenia. Meanwhile, Fargo gets assigned a new office somewhere in the depths of section 4 by Nathan Stark as a 'rite of passage'. While cleaning out all papers and such from the apparently forgotten office together with Henry Deacon, they find a very old computer from the Cold War era. When they activate the computer using two strange-looking keys find, a computer voice suddenly announces: "Primary firing sequence initiated. Weapons will deploy in 24 hours." Meanwhile, Jack is standing in the middle of the street handing out a fine, when the tarmac underneath him suddenly starts to shake and crack to reveal a 20 foot/6 meter tall missile-like structure rising up.
Soon after, Jack, Stark and Henry are down at Fargo's new office trying to work out how what exactly the weapon is and to try and stop the computer from counting down to zero. They are having problems since apparently no documentation about the computer exists on file. However, by then Henry has discovered that the machine is a weapon and that it's set to discharge a huge ionosphere particle beam, generated by irridiated uranium isotopes (or death ray as Jack likes to call it). Going through the papers they removed from the office, they notice all papers are initialised by the letters IT. They also find pictures of the moon among the files and Jack asks Henry what the shiny thing is in the photo. Henry tells him it is a mirror and that during the moon landing many of them were put on the surface to bounce signals back to the earth, like telescopic images, satellite communications and, as Jack hypothesises, "death rays". Henry tell Jack that using the mirrors to reflect the beam, whole cities could potentially be wiped off the map. Remembering the initials IT, Henry is convinced they must stand for "Irvin Thatcher", a brilliant scientist behind MAD - Mutually Assured Destruction
Jack goes to the retirement home to look up doctor Irvin Thatcher in the hope that he might be able to help them with a solution. However, when he meets the man, Irvin Thatcher seems to be out of contact with the here and now and even less coherent. Bringing him down to Fargo's new office also does not help. With the clock ticking down to 20 hours, Henry and Stark decide to take action and cut the blue wire ("red for hot, blue for not
") in the computer after a spectral analysis of the wiring. At first this seems to work, but instead of aborting the launch sequence, the countdown clock is reset to 7 hours. Having been forced into this dire situation, Allison suggests for Jack undergo an experimental procedure that will allow him person to probe the consciousness of doctor Irvin Thatcher (even though no human experiments have been performed yet). The procedure turns out to be extremely painful for Jack and mostly in vain, but among the various images from Thatcher's past, he sees some about a woman called Eugenia that Thatcher cared a lot for.
Jack and Zoe try to find Eugenia while in the street the weapon starts to activate. They finally find her in the park thanks to another flash from Thatcher's memory about a sun dial. They discover that Thatcher and Eugenia were a couple in 1962 and were going to get married in Stockholm, until suddenly Thatcher was not nominated for the Nobel prize and suffered a mental breakdown. Thatcher seems to be their only hope and they devise a plan to stage a Nobel prize awarding ceremony for him in order to bring him back to reality. When Thatcher sees Eugenia sitting among the holographic audience, he suddenly starts reciting his prepared speech about the ionosphere particle beam and regains clarity. Thatcher assembles his old team of now old men and with 30 seconds remaining on the countdown clock they arrive at the computer. They turn the keys in a specific order and the machine shuts down after a classic kick to the machine by Thatcher (with 10 seconds left on the clock). However, all of a sudden the machine comes alive again and the weapon's deploy is reset to 5 minutes because "somebody cut the blue wire
". With no means of shutting it down now, they all head for the surface and arrive at the weapon with 30 seconds left again on the clock. Finally, with a last thought, Jack and Thatcher come up with the idea of ramming Jack's jeep into the weapon to de-align it. With 2 seconds left, Jack successfully rams the weapon, causing it to miss the moon's surface (although it does manage to destroy the Rover approaching Jupiter).
Irvin Thatcher and Eugenia get back together and all ends well. Well, as well as can be.