白天担任急诊室医生的单身母亲Mary Harris，在晚上她兼职成为地下“死亡天使”，帮助重病症末期的病人依照他们的意愿结束他们的生命。长久以来Mary已经能够做到兼职时不被人发现，但是死亡太多，生意越来越红火，他她的双面生活也越来越复杂艰辛。当她的世界开始公诸于世时，她意识到如果她还想干这份工作，就要背水一战。

On St. George's Day, the morning of the local county fair (deriving its sense of place and community from the annual carnival week at Pewsey, Wiltshire[1][2]) Johnny "Rooster" Byron, local waster and modern day Pied Piper, is a wanted man. The council officials want to serve him an eviction notice, his son, Marky wants his dad to take him to the fair, Troy Whitworth wants to give him a serious kicking and a motley crew of mates want his ample supply of drugs and alcohol.[3][4] The play makes frequent allusions to Blake's eponymous poem from which its title is derived.