Sam is a struggling mum with an online gambling addiction, desperately trying to keep her life together after separating from her husband. With her ex, Dave, threatening to take her daughters away, Sam wants to prove she's a dependable parent to her two daughters, Alice and Lily. But getting back on track looks impossible for Sam with spiralling debts and having to a work zero-hour contract on the minimum wage as a cleaner in Canary Wharf making Sam's life is thrown into disarray when she discovers access to lucrative and illegal stock market information at the office she cleans. Realising this could be the answer to her prayers, Sam starts delving into the high-stakes world of the stock market. Persuading her best friend Jess to come in on the secret, the two cleaners start to navigate dangerous new territory.