The episode re-introduced Sarah Jane Smith, then-familiar to BBC Wales audiences after her appearance on Doctor Who a few months earlier in School Reunion. Simultaneously, it wrote out K9 Mark IV, whom audiences would have expected to see with Sarah Jane because of his appearance in the precedent Doctor Who story. Bob Baker, co-creator and owner of the concept of K9, was interested in getting K9 a show of his own, and so didn't want to dilute enthusiasm for the character by allowing his heavy use in The Sarah Jane Adventures.