On 7 January 2015, at about 11:30 a.m. CET local time, two French Muslim terrorists and brothers, Saïd and Chérif Kouachi, forced their way into the offices of the French satirical weekly newspaper Charlie Hebdo in Paris. Armed with rifles and other weapons, they murdered 12 people and injured 11 others. The gunmen identified themselves as belonging to the Islamic terrorist group al-Qaeda in the Arabian Peninsula, which took responsibility for the attack. Several related attacks followed in the Île-de-France region on 7–9 January 2015, including the Hypercacher kosher supermarket siege, where a terrorist murdered four Jewish people.

With unprecedented access to the French authorities and previously unseen footage, five-time Bafta-winning director Dan Reed reveals the untold story of the massacre and of the first Islamic State strike in Paris at a kosher grocery store.

Key witnesses, police officers and survivors - many speaking for the first time - piece together the dramatic attacks and the unprecedented manhunt that gripped the world for three extraordinary and terrifying days.