Dr Turner uncovers the cause of the recent spate of infant limb deformities. Realising that his own prescriptions could have exacerbated the tragedy, he jumps into action in an attempt to prevent further damage. Meanwhile, Nonnatus House is thrown into disarray by a tragedy even closer to home. Although Sister Evangelina is back at work, it’s clear that her recent stroke has affected her badly, and that her health problems are not over.