Hostage taking is when someone is taken against their will and held in a place where they cannot leave, usually by another person or a group of people. It's like when you're playing a game and someone takes your favorite toy and won't give it back until you do what they say.
Sometimes the person taking the hostage has demands that they want met before they will let the hostage go. It's like when you want a snack before dinner, and you won't stop asking until you get what you want. Except in this case, the demands can be much more serious and dangerous, like money or political power.
Hostage taking is not a nice thing to do, and it's very scary for the person being held captive. It's important to remember that taking someone hostage is wrong and against the law, and if you or someone you know is being held hostage, it's important to tell a trusted adult right away.