Sibling Bonds is the seventeenth episode of Lizzie McGuire's first season.
Lizzie has to attend a class charity drive and looks forward to spend the whole day with Ethan. At home, Matt irritates Lizzie with his magic tricks and he handcuffs himself to Lizzie and loses the key. Meanwhile, Jo finds the key and decides to remain silent about it so that Lizzie and Matt learn a lesson about family bonding, getting along, and looking out for each other. Lizzie has a hard time keeping Matt hidden from Ethan for the whole day leading to embarrassing situations.
Matt is irritating Lizzie with his magic tricks while she's trying to do homework. Soon they are fighting like cats and dogs--or brother and sister--much to the annoyance of their parents. But as soon as Sam and Jo stop them, they go right back to fighting.
At school Ethan Craft speaks to Lizzie and Miranda, but Lizzie is so tongue-tied she can barely utter a word. Mr. Escobar announces a charity drive and asks for volunteers. Lizzie thinks she'll be too busy until she hears that Ethan will be there. At home Lizzie is making some cookies for the event when Matt tries out another trick. This time he handcuffs himself to his sister, but he can't get the cuffs loose. Mom spies the key and hides it, thinking that if the kids are forced to spend a few hours chained together, they might learn to get along better. Now Lizzie is facing the horror of going to the charity drive with her little brother stuck on her arm!
At the drive, Lizzie tries to hide Matt as best she can while Kate takes advantage of the situation and steals Ethan's attention. Meanwhile, with the family gone, Dad settles back at home alone to enjoy the football game, but he OD's on junk food and falls asleep before the kickoff. Lizzie is furious with Matt for the trouble he's causing her, but she notices that he's particularly avoiding a bully named Heywood. When Heywood trips Matt, Lizzie goes ballistic and scares him off. Now Matt and Lizzie are beginning to understand some of each other's problems. Kate comes by to laugh at Lizzie's situation and to rub it in that she's with Ethan. Matt, returning the favor for Lizzie, comes up with a good way to get back at Kate. Dad finally shows up with the key and the siblings are released from their bond. Ethan sees Lizzie and tells her he thinks it's cool that she spent the day with her little brother. He invites her out for pizza with some friends, but Lizzie declines when she sees Heywood menacing Matt again, and she goes to his rescue.