Sweethearts are a soul band of 30 schoolgirls. They have a key rule: once a girl graduates high school, she leaves. With a third of the band about to graduate, Sweethearts are offered a rare European tour. Will they break their key rule?

In the pouring rain, Sweethearts undergo a dress rehearsal for Europe: six gigs in forty-eight hours. Trumpet player Tilly battles stage fright at having to sing. The recording session for the band's new CD runs dangerously behind schedule.

The second recording day for Sweethearts starts shakily when Chloe is late. Tilly co-opts Rachel to record a duet, but Ross cuts Rachel from the song. After starring at a Melbourne soul night, the girls play to a sparse crowd at their school graduation.

The band loses trumpet player, Kirsten. Elsbeth feels guilty for staying on. Jess is elected as the new band captain. The girls remember their lost loved ones at a fundraising gig for cancer research. Rachel pulls out of the tour.

Kirsten comes to terms with leaving while Maddi harbours a secret. The band works up a new song by Bree and Holly. Just when the line-up looks settled, Maddi reveals she has to leave Sweethearts as well.

Despite a strong tryout by Janeva, the new song Hate On Me is given to Chloe. Elsbeth has regrets about staying on as trombone mentor. Ross lays down the law to the vocalists and Tilly. Maddi doubts her worth to the band when Tilly takes on Maddi's solo.