Late night of April 25th 1986 a group of international scientists from International Atomic Energy Agency (IAEA) arrives at Chernobyl nuclear plant to test fourth reactor. A newly launched reactor of new type 'Samovar' is the most advanced technology known in atom for peace. There's one little complication though, a group arrived too late. It's 5:40pm and all the functionaries of MinAtom are out of reach in Moscow on their way to dachas. A clearance needed to run test can not be received till Monday.
Uneasy decision is to be maid. Either to get stuck for entire week-end in Pripyat, a nearby small town with one hotel and few if any attractions, or to run unauthorized test with full personal responsibility for any possible consequences. Furthermore, turns out that IAEA never received a paperwork alongside manuals from MinAtom for this brand new piece of equipment. To be received on Monday as well. In the result of lengthy dispute simple majority defines that unauthorized immediate test is to be performed.
Test's objective is to estimate reactor's cool down period after a critical overheat. Things go sideways soon after overheating. Reactor can't stop rising the temperature and an emergency operations are described in the manual. The missing manual.
Guess what? The group of scientists is you. It's only 60 minutes left before radiation reaches a critical level and the entire plant will blow up with you, causing the biggest nuclear catastrophe in the history of human being.
To end up on positive note, you've got 5 clues over magical walkie-talkie.
Don't burn them too fast, though!
Also, please keep in mind that nothing in Chernobyl needs to be vandalized, broken, torn apart, disassembled, unscrewed or climbed on. That will only make things worse ;)