Junior risk analyst Seth Bregman, alongside his senior colleague Peter Sullivan and trading desk head Will Emerson, witnesses an unexpected mass layoff orchestrated by a temporary human resources team right on their trading floor, all at the start of an otherwise routine business day. Among those terminated is their boss, Eric Dale, who led risk management operations on the floor. During his exit interview, Dale tries to convey critical information about an ongoing project, but the HR staff are more focused on his swift departure. As he is escorted from the building, he discreetly hands Peter a USB stick and warns him to "be careful" before stepping into the elevator.
Later that evening, Peter delves into Dale's project and uncovers alarming news: the inherent volatility in their mortgage-backed securities portfolio is set to surpass historical levels. This analysis reveals that due to excessive leverage, a mere 25% decrease in these assets could result in losses greater than the firm's entire market capitalization. Realizing the urgency of the situation, Peter alerts Will, who in turn connects with floor head Sam Rogers.
The employees remain at the office, engaging in a series of urgent meetings with senior executives, including division head Jared Cohen, chief risk officer Sarah Robertson, and finally CEO John Tuld. Jared proposes a rapid sale of all toxic assets before the market catches wind of their devalued state, a suggestion that John prefers despite Sam's fervent opposition. Sam cautions both Jared and John that offloading these risky assets will send shockwaves throughout the financial sector, jeopardizing the firm’s relationships with many stakeholders. He also points out that their clients will quickly grasp the situation when they realize the firm is simply unloading toxic mortgage-backed securities without engaging in any form of trade.
In a twist of events, the team eventually tracks down Dale, who has been unreachable since his termination. With the promise of a generous payment and the threat to contest his severance, they convince him to return. In the midst of the chaos, it becomes clear that Sarah, Jared, and John had been aware of the looming risks leading up to this crisis. Tuld plans to present Sarah’s resignation as a scapegoat to their board and staff.
As the market prepares to open, Sam rallies his traders with the incentive of seven-figure bonuses for a drastic 93% reduction in certain mortgage-backed securities through a "fire sale." He acknowledges that this action will irreparably harm their professional relationships. Meanwhile, Sarah and Dale find themselves in a stifling office, earning hefty pay for doing nothing, while Sarah defensively claims she had indeed warned about the emerging risks, albeit not assertively enough. As Emerson starts executing the necessary trades, tensions rise among counter-parties who grow increasingly restless as the day progresses.
When trading comes to a close, Sam witnesses the same human resources team initiate another round of layoffs within his department. He confronts John, expressing his desire to resign, but John dismisses the severity of the crisis, equating it to past market downturns and asserting that sharp financial fluctuations are merely a facet of the economic landscape. He persuades Sam to stay on for another two years, with promises of significant profit to be gained from the impending crisis. Meanwhile, Peter is seen discussing his projected promotion with Jared, while it seems Seth’s tenure at the firm may soon come to an end.
In a poignant closing scene, Sam is depicted burying his beloved dog on his ex-wife's lawn, a heart-wrenching reminder of the personal toll amidst the corporate turmoil.
