3rd & Bird - Playhouse!

Muffin stumbles on Samuel and Rudy's playhouse, but they won't let her come in. She stomps away and Quinn helps her build her own playhouse, even better than theirs. When Samuel and Rudy ask to visit, Muffin won't let them. Mr. Beakman suggests they stop quarreling and put the playhouses together. They take his advice and make the best playhouse ever.

This is episode 21 of Season 1.