[S.T.A.L.K.E.R.] Series.
On your last adventure, you successfully retrieved a box of ammo and could stay a night in the abandoned house.
On your way back, a storm came up and you found shelter in a hideout. After you've done some trading, there were people talking about old computer parts containing informations about some artifacts nobody has found yet. After investigating these rumours, you could find out that everything's hidden in an old, closed mineshaft. Since it's not that far and a pretty safe area, you decide to give it a visite before anyone else does so. Good luck!
(Depending on how tall you are it could be difficult to reach the cache and you have to climb a bit, or have a friend helping you out. Also, please place it back where you found it, or at least so that I can't be seen! There's also no trespassing. It's just a name chosen on the base of the game.)