The Incident at CovColCosCon (S01E04)

Helen's long-anticipated day has arrived – the Coventry Collectibles & Cosplay Convention is finally here. Elton is getting ready to accompany her with her Dalek costume in tow. When Gus learns that his idol, the brilliant Dr. Peter Toynbee, will be giving a talk at the event, he eagerly decides to tag along, bringing Richard with him as well. However, beneath the surface of the convention center, dark and unsettling happenings are unfolding.