Liz tries to discover if Alex was killed by an alien - with shocking results.

Written by Gretchen J Berg & Aaron Harberts
Directed by Patrick Norris

The death of Alex and the divisions between humans and aliens make this an intriguing episode. Liz in full detective mode is gripping as she uncovers more of the mystery around Alex's death, and the strange truth about his trip to Sweden. Last week we thought she was a nutter - now this week we realise the only thing keeping her going is the strength of her convictions.

Meanwhile, in the background, the alien/human divide causes some pretty cool developments. Not only do Liz and bad boy Sean start to get it together, but Max, in full insuferable prig mode, not only manages to completely alienate Liz and Isabel, but also ends up shagging Tess. Disaster.

Finally, just as we're trying to get over the full horror of what Max has just done, this episode delivers its killer punch... There was a reason those slides of Alex's trip to Sweden looked so unconvincing - he never went to Sweden.