The arrest of young drug dealer Sandy McKnight begins to expose a criminal conspiracy involving every level of Belfast's society, from wealthy businesswoman Dana Morgan to vulnerable teenager Lindsay Singleton.

A car crash has traumatic consequences for Aisling, while the fallout creates a deadly situation for the section. Grace turns to child protection to try and help Lindsay.

Grace and Shane push boundaries for Lindsay's sake as a threat closes in. Aisling and Tommy respond to a call-out where things are not as they seem, with unexpected consequences.

Grace and Sean bring in George for questioning, leading Morgan to take drastic measures to silence him. Shane faces an unexpected situation on a routine call-out.

Grace and Sean are under serious threat, while Lindsay's testimony exposes the Ginleys. Colly takes a risk to go after Morgan, and Fogerty decides Tina is no longer useful.