In December 2004, Big Finish released ', the first audio drama in a "UNIT" spin-off series, which features a retired General Sir Alistair Lethbridge-Stewart as an advisor to a new generation of officers. A preview episode (given away free with "Doctor Who Magazine" #351, and later available as a free download on the Big Finish website), ', has Lethbridge-Stewart finally breaking decades of secrecy by informing a press conference of UNIT's true purpose as humanity's first line of defence against the unknown (although, as it turns out, the general public believe this to be a hoax). The series also introduced another rival division, this time within the British government, the Internal Counter-Intelligence Service, or ICIS.