at one stroke

I made up my mind that a man confined to his room by inflammation of the lungs, a fellow who had only two wishes left in the world, to see a particular woman, and then to die, could neatly accomplish those two wishes at one stroke by taking this journey in the rain.

[T]he whole object of the poem is to show what infinities of spiritual good and evil a current and sordid story may contain. When once this is realised, it explains at one stroke the innumerable facts about the work.