Theory:

The lesson "Man Overboard" is about the sea trip experiences of a little girl named Vasantha Murthy. She travelled on a ship alone called S.S. Rajula once while travelling to Singapore, returning from her grandparents' place.

On the second day of her journey, a warning about a heavy storm on the Indian ocean created much commotion among the ship passengers. Still, it did not affect Vasantha in any way. She was happier only after the announcement was made as she was fond of adventurous journey.
 
While there was no such expected calamity had happened, there was a heavy wind still. As Vasantha was highly fascinated with adventurous journeys, she went to the ship's deck to enjoy nature's work. During that time, she encountered an issue where she accidentally saw a man slipping into the sea. She then immediately shouts for help.

It was the captain himself who responded to her cry. He took the initiative of leading his crew in saving the victim's life. He instructs his team carefully and quickly to save the victim without any delay. His experienced sailors manage to do so by dropping life-boats on the sea near the victim and saved his life successfully.

Vasantha's presence of mind, immediate call, captain's response, crew's team effort, and sailors' experience altogether saved a life. Everyone, including Vasantha, was relaxed after that successful rescue operation. A nurse from the ship's clinical section gave her assurance about improvement on the victim's health, which kept Vasantha's mind peaceful.

The captain of the ship surprised Vasantha with a fabulous gift to appreciate her excellent work. It was a beautiful sculpture of the ship on it was written, "B.I.S.N. & Co. S.S. RAJULA." It made Vasantha's day. She happily displayed her gift to everyone on the ship, and she was the happiest person on the ship on that day.