Back again and season 5 of Buffy saw a new addition to the cast, the addition of Michelle Trachtenberg as Dawn, Buffy's little sister. This addition was instrumental to story arc of this season as fans would come to realise and would have devastating effects for all our favourites.
The big bad of this season is Glory, a god from another dimension who cannot get home without "the key" and she will do anything to find it as we witness when she captures Spike and tortures him for information. However, with his new found crush on Buffy he does not give Glory anything and eventually is rescued by Buffy herself. It is later revealed that the reason none us of fans knew Buffy had a sister in any of the previous seasons was because she doesn't. Confused? Well it turns out "the key" once on Earth had taken human form, somewhere it would be protected and as such altered people's memories of its existence. Therefore Dawn is "the key" that Glory is seeking, resulting in a very large confrontation between the Scoobies and the God that results in the death of one our favourites, bringing tears from all.
How will the gang survive? Stay posted to find out, ttfn :)