In 1982, two families, the Sanders and the Landrys, are badly shaken when they learn that a mysterious deadly disease called AIDS is threatening the blood system. Each has boys with hemophilia, a genetic condition that means they depend on blood products to live. The medical community struggles to understand the growing epidemic while others deny the urgency.

With his son's life hanging in the balance, Will Sanders desperately fights to get those in charge of blood safety to heed the danger. The Landry's struggle to keep their family together after their son, Peter, distraught that he is likely infected with AIDS, leaves home. Dr. Christos Tsoukas publishes results of a study that suggests fifty percent of all hemophiliacs in Canada are HIV positive.

In 1985, Will Sanders questions why the Red Cross may still be distributing tainted blood when safe heat-treated product is available. Margaret Sanders battles the prejudice surrounding AIDS. Lawrence Hartley and Paul Kirpatrick, both infected hemophiliacs, lead the charge for victims, while waiting on HIV test results for their wives. Peter Landry spirals out of control to Ben and Alice's dismay.

In 1987, hemophiliacs untouched by AIDS believe blood products are safe. But one company's heat-treating process proves flawed and seven more people, five of them children, are infected. Brash and outspoken hemophiliac, Jim Krepke joins the fight. Will has a victory while Ben seeks direction. Alice and Peter try to pull themselves together.

Over the early 90's, victims of tainted blood begin to come forward and pressure the government with lawsuits. With Margaret's help, the Hemophilia Society works tirelessly behind the scenes for compensation. Lucky to avoid HIV, Ryan Sanders suffers through the side-effects of treatment for Hepatitis C. Peter meets Darby and despite his HIV, they fall in love. Having finished the archival history, Ben starts work on a more personal book but it causes further rift between him and Peter.

The supreme court rules in favor of Krever and his report finally comes out. It names many for wrongdoing and aims to rebuild the flawed blood system in Canada. While victims still suffer and loved ones mourn the dead, at least many feel that their voices were heard and those responsible were held accountable. But Ben is not satisfied and pushes for criminal charges.

As the criminal trial falls apart, Ben considers taking matters into his own hands. Peter and Ryan both struggle with illness while forging families of their own. In 2015, both of their lives hang in the balance as the tragedy finally threatens to catch up to them.