After she is imbued with the power to kill with a touch, a grieving farmer must stop a trio of fundamentalists intent on recruiting her as the fourth "horseperson" of the apocalypse before they can end life on Earth.

I think what you're really indicating to me here is that the inciting incident I've described (the magic power being bestowed upon her) doesn't directly relate to her goal.

So what I should really be indicating is that after she refuses to join their group - and having the knowledge of what they plan to do - that's when she would be faced with the responsibility of stopping them.

I'll rethink the logline. Cheers.

I really like this idea but what is the drive to save the world? because she is grieving, not sure about that.