The threat: the destruction of all life on Earth.
The agents: a young man with a system, and a military woman in charge of Bureau of Supernatural Affairs.
Albert woke up and saw a Quest waiting for him, from a [System] that had not come without reason. Its purpose was to give him power to fight an invasion of Earth at the hands of an unknown species.
One day, one step at a time. First, he must become strong.
And he is not alone. There is another: a woman of pure steel and resolve working against all odds to save humanity.
Slow start, then the pace picks up. Stakes are real. Choices matter. Characters make mistakes. Progression makes sense and no power creep. No dumb villains. No plot armor.