"A Child's Heart - Part One" is the 962nd episode of Casualty and the premiere of the 30th series. It was preceded by "Forsaking All Others - Part Two" and followed by "A Child's Heart - Part Two". The series premiere two-parter featured all of the main cast members, a rare occurrence. The two episodes also didn't take place on the date they aired, unlike other episodes. Instead, the events took place directly after the series 29 finale, continuing the story in the evening of 23 August.