Born into a happy working-class North London family in the mid-twentieth century, Katie is determined to 'do something' with her life. Working in the impoverished East End in the 1950s, she meets the Sisters of St John the Divine, a community of nuns dedicated to nursing and midwifery. The Sisters have been present at births, cared for the sick and laid out the dead of the East Enders for a hundred years, and Katie soon joins them to start her journey to becoming Sister Catherine Mary.
As a nurse and midwife, Katie learns to deal with everything from strokes to breech births. Tragedy is never far away, but there are also moments of pure joy as lives are saved and the Poplar residents rally round. As a young novice Katie rallies against the vow of obedience, yet over the years learns much about the nature of dedication and love.
Full of desperate hardship, humour and compassion, Katie's story brings to life the unique world of these nursing Sisters in London's East End.