Stargate Atlantis

When SG-1 finds a vital clue in its search for the Lost City of the Ancients, Dr Weir prepares her team for a perilous journey under the sea.

A game causes one of the Athosian children to open a unit and unleash a dark entity. They soon realise that the harmless-looking cloud is anything but.

Fleeing from an encounter with the Wraith, the team's ship gets lodged in the Stargate. Meanwhile, Sheppard is paralysed by an alien symbiote feeding off his life force.

Relationships are torn apart and tensions run high when Dr Weir suspects the crew's new friends, the Athosians, are harbouring a spy.

Sheppard and the team visit a place where no-one seems to reach the age of 24. They soon discover that ritual suicide is an integral part of the local culture.

The team encounter a human civilisation, the Hoffans, recovering from a Wraith attack. Do they have the knowledge to create a weapon to combat the enemy?