The tailhook scandal happened a long time ago in the United States Navy (like your grandpa's time). It was a big problem because a lot of people did bad things and it caused a lot of anger and confusion.
In the Navy, there are special groups of people called pilots who fly planes. Sometimes the pilots have to land their planes on big ships in the ocean, which is really tricky. The pilots have special hooks on their planes, kind of like a fish hook, which they use to grab onto a wire on the ship, which helps them stop their plane.
At a big party for Navy pilots, called Tailhook, some of the pilots did bad things to other people at the party, like touching them in ways they didn't want. There were lots of complaints about these bad things, but the Navy leaders didn't do anything to stop it.
People were very upset that these bad things happened and that nothing was being done about them. Eventually, the Navy had to do something to make things right, so they punished the pilots who did bad things and changed some of the rules to make sure it doesn't happen again.
The tailhook scandal was a really important lesson for the Navy and for everyone else. We should always treat other people with respect and kindness, no matter who they are or what they do.