Okay kiddo, let's say you find grandma's missing diamond ring on the floor. You want to give it back to her but you don't want to get in trouble for losing it or someone thinking you stole it.
That's where the chain of custody comes in.
It's like a special way of making sure nobody can mess with the ring or lie about where it came from. It's like the ring is like a baton in a relay race, and there's a special team of people who have to pass it to each other very carefully so nobody drops it or touches it in the wrong way.
These people are called the "chains" or "links" of custody. They write down every single thing they do with the ring, from when they found it to when they gave it back to grandma. They also make sure nobody else touches it or takes it without permission.
This way, if there's any question about who had the ring or what they did with it, the chain of custody can show exactly where it was at all times. It's like a trail of breadcrumbs that shows everybody who looked at the ring and what they did with it.
So when you give the ring back to grandma, you can show her the chain of custody and tell her the whole story of how you found it and made sure it was safe. And she can be happy knowing that the ring was well taken care of and nobody messed with it.