Set in Cardiff, Wales, Torchwood is a darker, more enigmatic offspring than its parent show Doctor Who, with a dash of sex and an edgier outlook. Filming of Season 2 quite literally started with a bang. The BBC was forced to issue an apology for sparking terror fears after an explosion scared passers by and sent a huge pall of smoke over Cardiff's city centre. The explosion was staged in an old courtroom building next to the Millennium Stadium.

Police and BBC warnings on local radio hours before had not been enough.

"We had informed neighbouring businesses but could not tell everyone who might be in the city centre," said a BBC spokesman. "We apologise if anyone was frightened."

Created by Russell T. Davies, the man responsible for Doctor Who's recent renaissance, Torchwood's well-received first season introduced a raft of disparate characters and strong narrative themes that focused on morality, relationships and, of course, weird alien happenings. The title itself is an anagram of "Doctor Who" and the apparently indestructible lead character Jack Harkness (John Barrowman) first appeared in the revitalised Doctor Who's first season.

Torchwood is a secret organisation that solves alien and human crime and, along the way, collects alien artefacts and protects humanity. Cardiff is at the centre of a space-time rift that regularly spits out artefacts and creatures for the team to deal with.

According to reports large-scale changes are coming to the show. Russell T. Davies believes they made some mistakes with plotting and character development in Torchwood's first season that needed to be improved this time round. The first episode title "Fresh starts" seems to suggest he's done just that.

Hopefully they don't replace too many of the key characters that worked so well together in Season one; especially their leader Jack, the morally flawed medic Owen Harper (Burn Gorman), and the curious and sometimes naive Gwen (Eve Myles).

James Marsters, best known as Spike in Buffy the Vampire Slayer, will make a guest appearance, as will Neighbours / Ugly Betty star Alan Dale. Marsters has been quoted as saying he will play "a bit of a psychopath".

Scripted episodes feature a rogue time agent and a time slip from World War I. Perhaps this season we'll also see a cross over episode with Doctor Who?

Filming of Torchwood's second season started in April and will continue until the end of November. In the UK, it's expected to air in January 2008.