Duffy returns to Holby as an agency nurse as the medical drama series begins a new season with the first half of a two-parter that concludes tomorrow. It should be the happiest day of Zoe and Max's lives, but things go disastrously wrong at what turns out to be an explosive wedding reception, resulting in more than one member of staff fighting for their lives. At the same time, the victim of a gunshot wound is brought into the Emergency Department. Jacob implements the emergency procedure designed for such occasions, but the team struggle to prevent gang culture from infiltrating the department, as one casualty leads to more.