Jane Espenson of Buffy, Battlestar Galactica, Caprica, Torchwood, Husbands, Once Upon a Time.

“Selecting the moments that will be the act breaks is crucial. Writers who are just starting out, writing sample scripts that they will use to find that first job, often fail to realize this – I remember changing what the act break would be in a script because I wanted it to fall on the correct page. This is a bad sign. The act break moments should be clear and large. In my Firefly episode, “Shindig,” the third act ends with Mal stabbed, badly injured, in danger of losing the duel. It does not end when Mal turns the fight around, when he stands victorious over his opponent. They’re both big moments, but one of them leaves you curious and the other doesn’t.”

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James Moran- Torchwood, Dr. Who, Severance among others.