GSC Game World has a dangerous thrill waiting for S.T.A.L.K.E.R. 2 fans.

They made this announcement on Twitter:
Stalkers!
A free content update, Sealed Truth, is coming in April to celebrate the Cost of Hope DLC announcement — you will be able to open the door to X-18 Lab.
And who knows what’s hiding there in the darkness…
Stay tuned.
X-18 Lab is a modification of Lab X-18, which was originally seen in S.T.A.L.K.E.R. Shadow of Chernobyl. This laboratory is found deep in the Dark Valley, and was run by the Military.
The Military experimented with psychic radiation on human subjects, with increasingly terrifying effects. We won’t spoil any more plot points here, but if you’re an old S.T.A.L.K.E.R. fan, you know what GSC Game World is hinting at here.
This update may also include plot points of their own that sets up S.T.A.L.K.E.R. 2: Cost of Hope. So this could be indispensable for those longtime fans.
