ACT I. The Brink of Winter, 1892. Our story opens on a young, homeless woman Amber Murray, nursing baby Horace, under a tree in a city park in the winter. Desperately cold, but stoic, she shields her son from the rain (The Hymn).
Amber visits the offices of the Herald after learning that its trading column accommodates for 'temporary baby-trading', (whereby a mother could advertise her infant to be temporarily cared-for by a wealthier family). Assured that this might provide her with some time to secure a job and home, Amber 'advertises' Horace in the buy and sell column. The kind couple- Charles and Agatha Makin, who make their living from professional child-minding- answer the advertisement and take Horace into their care (Twisted Little Town / Puddles)
In her search for work, Amber visits the Makins, (including their peculiar teenage daughter, Clara) to pay the compulsory fortnightly premium for the upkeep of her child. She is kept from seeing Horace, however, and is provided with increasingly odd excuses about his whereabouts on a regular basis (Work). Relief comes when Harriet Piper employs Amber, and an extraordinary friendship begins. Amber reveals to Harriet how she has been kept from seeing Horace. Angered, Harriet beseeches Amber to demand answers.
Amber goes in search of other mothers who have handed their babies over to the family. Like Amber, these mothers have also been kept from seeing their babies but have been consistently paying the premium, regardless. They refuse to help her further, however, for fear of the shame of their choices (Knock Knock Knock / Gathering Sirens).
Meanwhile, Charles Makin visits Harriet at the fruit-shop while Amber is gone, demanding his payment. When it is refused him, he threatens Harriet and demands that she tell Amber that he and his family are moving far away. Harriet and Amber rush to their house to demand Horace’s return, only to find the family have already gone. Without leaving an address. Harriet does her best to console the despondent Amber (The Hand Of Courage).
Amber takes off in search for them, refusing to believe they could have moved so far in the middle of the night, only to discover all of Horace's precious clothes have been pawned to a merchant in the early hours of the next morning (These Things / Twisted Little Town Reprise).
ACT II. Months have passed when a drainer unearths 'little white bundles' in the yard of a Makin residence. (Digging Up). To the shock of the city, the Makin family, including their daughter Clara, are arrested after thirteen infant bodies are found. Amber resolves to fight the Makins in court and encourages the other-mothers to do so as well. (Holding You Horace)
A media circus ensues (Headline). Amber is badgered mercilessly by the attorney for the defense - and the judgmental public - for abandoning a child born out of wedlock. In a heartbreaking test of her own will, she is forced to prove the identity of her son. (Why Did I Give Him Away?). After every other mother has failed to do so, it rests on Amber’s ability to prove-identity in order that further criminal trial may take place. When the clothing the child was buried in is presented to Amber, she reveals a piece of lace that matches the baby-gown and shirt exactly. She is the only mother who has successfully identified her own child at the inquest, resulting in a murder trial for The Makin family that Amber must fight alone.
During the murder trial, Williamson- the attorney for the Makin family- reveals the fundamental importance of Corpus Delicti- the need for proof of murder. As none of the bodies show any immediate sign of murder, he insists it would be an assumption to hand over a guilty verdict for murder in this case which would, in turn, create a dangerous precedent for “the future of the mistakenly accused”.
Amber confesses to Harriet that Horace had, in fact, been ill when she gave him over to the family. Meanwhile, Clara Makin, locked in a cell with her mother, accepts the truth of her upbringing: she is not the daughter of Charles, but is, in fact, another child born out of wedlock who has been kept from seeing her real father- who has long been in search of she and Agatha (Sail).
Harriet nurses Amber, broken and exhausted, through the night (Something Like Being A Mother).
On the stand, Agatha and Charles claim innocence- insisting that the babies were taken by natural causes, claiming guilt only for illegal burial (Natural Causes).
Finally, Clara Makin- takes the stand and exposes her parents as desperate and greedy murderers who used a Hatpin to murder the children (The Hatpin). She reveals a journal, written by her mother, that verifies her claims. Free of her secret, she is dragged from the court, Agatha is imprisoned and Charles hanged (The Verdict).
With the friendship of Harriet and the spirit of Horace within her, Amber leaves the city to restart her life. No longer bound by fear or desperation, she moves into an unknown future in the light of a new day (The Tiny Glow / Sail Reprise).