It's the teacher who is going to tell a story. Teachers often use storytelling as a teaching tool. They can use stories to illustrate complex concepts, introduce new topics, or just to build a connection with the students.
It's hard to say. While he has the ability to tell a sad story, he also has a lot of positive and upbeat experiences. It could just as easily be a happy or inspiring story.
Maybe it's an adventure story. You might be about to tell a tale of a brave hero exploring uncharted lands, facing dangerous creatures and solving mysteries along the way. For example, like Indiana Jones exploring ancient tombs.