What Is a Summary of the Short Story "Luck" by Mark Twain?

"Luck" is about an English captain named Lord Arthur Scoresby who seems to be a complete idiot but, despite his incompetence, is so lucky that he manages to be acclaimed as a hero and a military genius. The story is narrated by a clergyman who is obviously envious of the captain's success. It is unclear whether the captain is truly incompetent or only appears so in the clergyman's eyes.