A British gentleman is traveling from London to Brindisi, in India. On the train, he meets a man named Colvin, who asks to share his cabin on the ship they're both taking.
In India, Colvin used to be friends with an Englishman named Broughton. They both moved back to England, where Broughton settled down, married, and moved into Thurnley Abbey, an ancient manor that was rumoured to be haunted. These rumours were fed by the previous owner, who hated people. Broughton doesn't fully believe in the ghost, and even if it exists, he seems unworried.
Skip forward six months. Colvin gets a letter from Broughton asking him to come to his house - he needs help. Colvin does, and passes a pleasant evening at a dinner party Broughton hosts. Then it's time for bed.
Then, of course, Colvin sees a ghost. It's a skeleton wrapped in in rags, hovering at the foot of his bed...