Not a bad draft of a logline, Miroslav, but there are just too many vaguely-handled details. This is a very common issue with loglines from writers who are too focused on not giving much away and, consequently, end up giving us not enough.

For example, "a notorious place" - where is this? how is it notorious? "something unexpected" -- too ambiguous, so we can't glean anything significant, and the same goes for "beyond any human comprehension" - how so? This then leads to a final sentence clause that. because of the vague detailing that's gone before it, means very little to the reader. "their only goal is to fight for survival at any cost" - how is this so? How can we comprehend the goal, the stakes etc. when you've given the reader such a dearth of information? It feels too generic, too placeholder.

Moving forward, I would strongly advise you include some salient details, especially about the goal, the opposition/antagonistic force, and the stakes, so we can get more of an understanding about what this group of assassins is up against. This will also better define your story, communicate a stronger U.S.P. and allow it to live in the mind of the reader. Best of luck, and by all means get back to me if you'd like to talk further.