Shaun Riley is a late twenties slackabout who lived with best friend Ed and former college roommate Pete. Despite holding down a day job as a sales advisor at a local electronics store, Foree Electronics, Shaun suffered from a serious unwillingness to take initiative and do things, preferring instead to drink at his local pub, the Winchester, with Ed; it was largely this which brought him into trouble with his girlfriend Liz, who eventually dumped Shaun after he failed to book a table for them at a local restaurant. He also had serious issues with his mother, Barbera, and her second husband, Philip; Shaun and Philip's relationship had been nothing but antagonistic since Philip arrived, prompting Shaun to avoid his mother as often as possible, and "failing" to introduce Liz to her.
He was also a very protective, almost big brother figure, to the slovenly Ed, who constantly embarrassed and humiliated Shaun. Shaun and Ed have been friends since childhood, and the relationship also placed strain on Shaun's relationship with Liz.
After a big night on the booze to drown his sorrows, he and Ed awakened in the middle of a full-scale zombie epidemic. Whilst many panicked and ended up dead, Shaun found himself purposefully-charged, a mission dropped into his lap, that he must see through no matter what: to ensure Liz's safety, and that of his mother, before finding a place to hide everyone until the situation "all blows over". Complications- having to drag an infected Philip and Liz's abhorrent flatmates David and Diane with them- didn't stop Shaun's momentum, and he turned from Shaun Riley, mild-mannered appliance salesman, to Shaun of the Dead, zombie fighter... well, almost.