Short answerThe in-story year drives every costume, set and prop the renderer draws. A wrong or missing year sends the whole series to the wrong century, and episodes already rendered keep their look.

The Era / year field on the brief is the single date the whole production reads. Character anchors, four-view sheets, scene sheets, props and every rendered shot are prompted with it. A period drama set in 1587 gets Ming attire, lamps and furniture; a drama set in 2026 gets phones and cars.
The field is required. The wizard will not let you submit a brief without a numeric year, and it is deliberately not prefilled: a default year is exactly how a period show ends up in modern dress.
We have watched it happen. A series written as a Ming-dynasty story but created without a year was rendered as if it were set today: the first two episodes looked right because the writers had described period costume shot by shot, and from episode three the cast appeared in modern clothes. Nothing in the scripts had changed; the renderer simply had no era and used the present.
The costume drift is only the visible part. Sets, props, vehicles, lighting and even gestures follow the same date.
The year is read at render time. Correcting it changes every render from that point on and leaves finished takes untouched. You do not have to re-render episodes that already look right.
Use a plain number: 1587, 1920, 2026. Add the dynasty or decade in the premise if it helps the writers, but the number is what the renderer reads.
Still stuck? Email support@dawnwood.ai with your account email, the series, the episode and the segment or group — see what to include.