Hetty's feisty little borrowed-sister, Eliza, arrives at the hospital and like Hetty clashes with Matron. When Matron's sister, Annie arrives to deliver bad news about their dying mother, she also tries helping Eliza and Hetty in their battles with Matron. But can Annie help her own sister make amends with their frail mother before it's too late?

The boys compete in a series of grueling army tests in order to win a place out of the Foundling Hospital and into the big wide world as a drummer boy in the army. With Vince determined to beat his main rival Mathias, a bitter battle is set to turn nasty. Meanwhile, Hetty and Sheila are forced to work together in the Infirmary as nurses tending to a sickly boy, Charlie. But will their rivalry get in the way of looking after the ailing patient?