B. J. Harrison Reads The Gloria Scott

Sherlock Holmes is still a student when he receives his very first case. While still in college, he is invited to the house of his good friend, Victor Trevor. There he meets Trevor's father, who challenges Holmes to analyze him, so that he can test the young detective's investigative skills. Holmes touches a nerve after mentioning a person with the initials "J.A.". After the shock passes, Trevor's father tries to hide how terrified he is, but Holmes can still catch the anxiety in his eyes.
Why did Trevor's father get so scared after he heard the initials? Whose are they and what does their possessor have to do with the father? Who or what is Gloria Scott? Will Holmes be able to complete the case and reveal the truth? Is he good enough?
This story about mystery and fear of the past was first published in 1893.