Spock is a main character in the popular TV show "Star Trek." He is half Vulcan, half human. A Vulcan has no emotions but is extremely smart and logical. Spock joined the all-human crew of the spaceship Enterprise to explore the universe. Spock's dad, Sarek, is Vulcan. He had wanted Spock to attend the Vulcan Science Academy and then join Sarek's research firm. When Spock left his family to join the Enterprise, Sarek refused to talk to him anymore.

In one episode, representatives from various planets had an emergency meeting. Sarek and Amanda (Spock's human mom) came aboard the Enterprise. Spock said hello to his dad, but Sarek ignored him.

The next day, Sarek had a critical medical problem. He was losing a lot of blood and needed immediate surgery. Spock was the only one on the Enterprise who also had Vulcan blood. Even though he could die, Spock offered every drop of his blood to save his dad. Dr. "Bones" McCoy operated on Sarek and saved his life.

The next day, when Sarek was told that his son had saved his life, he didn't say thank you to Spock. Amanda got very angry with her husband. She told him that he should hug Spock and thank him. Sarek refused. He said that his son did the logical thing.

"You don't thank someone for doing the logical thing," he told his wife. Spock told Amanda that his dad was right, which made her even angrier.