"Where's Mary?" is played while Jack and Mel wait for Mary to arrive. Mary arrives, running in the clubhouse with a seed she got from the plant store. Mary runs to where Jack and Mel usually play music, at the back of the clubhouse. Jack and Mel tell Mary that they are practicing at the front of the clubhouse. Mary runs to Jack and Mel and shows them her new friend, a seed which she named Arthur. Jack is impressed with the seed, he thinks it looks cool. Jack asks Mary what kind of seed it is, and Mary doesn't know. All the guy at the plant store told her was that the seed will grow into a super-swell special flower. Mel has an idea. Mel wants Mary to plant the seed in the clubhouse. Mel brings over a pot with dirt in it for Mary to plant the seed in. She plants the seed in the pot, and then Mel brings over a watering can. Mary pours the water in the pot. Then, Mary takes the pot to the window for sunlight. Mary impatiently waits for the flower to grow. Jack explains to Mary that it usually takes a while for a flower to grow. Mary agrees, saying that Arthur is her new friend, and she is so excited to see the flower grow, and bloom. Once that happens, the trio can find out what kind of flower Mary has. The trio plays music to pass the time. "What Will Arthur Grow Up To Be" is sung by Mary, with Jack and Mel playing instruments. During the song, Arthur starts to grow. Mary notices this, then tells Jack and Mel. They look closer at the new plant. Mel thinks that the flower is growing to music. Mary has never heard of this, but continues to play music with Jack and Mel to find out. The flower continues to grow. They play music again to see if this is true once and for all. The flower continues to grow to the music. Mary says that they need to play really fast. The quicker the music is playing, the quicker the flower will grow and bloom. Mel suggests speed polka, and the trio plays polka music really fast. "H20+02+Sun" is played. Back at the clubhouse, everyone except for Mary is getting tired from playing speed polka. Jack tells Mary that they need to take a break. Mary doesn't like that idea and continues to play music. Jack and Mel, who are resting, look at Mary while she continues to play. Eventually, she gets tired too. Now there is no music for Arthur to grow to. The Schwartzman Quartet enter, performing "Mary". This makes the flower continue to grow. After The Schwartzman Quartet leave, the flower is huge. "Running Down The Hill" plays. Back at the clubhouse, Jack and Mary continue to play music for Arthur. Arthur is now really big. Mary, however, notices that Arthur is no longer growing. Mary, now worried about Arthur, tells Jack and Mel about this. They all wonder why Arthur isn't growing. Cathy then enters, one last time, and Mary brings the plant to her. Mary asks Cathy why Arthur isn't growing. Cathy explains that Mary's flower is a Daddio Flower, which means that it only blooms to jazz music. The three ask what jazz music is. "Playing Jazz" is played. Jack plays the bass, Mary plays the saxophone, and Mel plays his drums. The three of them play jazz music for Arthur, which makes Arthur bloom. Cathy leaves after the song, and Mary says that Arthur will love living in the clubhouse.
This episode is Cathy Richardson's debut in production order and her final appearance in airing order, making her be gone for a while in production order and forever in airing order.
In this episode, Cathy said that she was going to see the cool jazzy cats later, but she was just joking. She guesses that she won't.
When Cathy leaves forever, the episode comes to an end.
Goofs[]
A hole can be seen in Jack's shirt during "Playing Jazz".