Soo In, Bok Nyeo, Poong Geum, and Mi Oh were cellmates in an all-women's prison. Though they all came from different backgrounds and had their own reasons for being in jail which later turn out to have a common thread intertwined, they were able to come together as friends through bakery lessons offered by the prison. As they grow closer like sisters, forge a bond based on their common grievances and lean on each other for support and become more talented bakers they make plans together for life after prison: to open their own bakery and challenge a big conglomerate, Shinhwa Bakery, for an exact revenge.