Mouse was another band project led by the legendary British prog-fusion and session guitarist Ray Russell, following Rock Workshop and Running Man. Together with keyboardist and singer Alan Clare, Jeff Watts – who had previously played bass with Steel Mill – and Alan Rushton on drums, they recorded their debut album in 1973 at De Lane Lea Studios in London, co-produced by the band and John Acock, who also acted as sound engineer. Lady Killer was released in England in December of the same year on the recently founded record label Sovereign, a short-lived, two-and-a-half-year-old subsidiary of the major label EMI.

On their first LP, the quartet presented a versatile and unconventional mix of guitar-driven hard rock with prog and psychedelic elements, synthesiser-heavy pop-rock, as well as Delta blues and even glam, led by a virtuoso acid lead guitar. However, this outstanding musical performance, full of sophisticated production details and accompanied by a provocative cover design by Glenn Pierce, failed to impress the public. Following this commercial failure, the band disbanded shortly afterwards and Ray Russell returned to his work as a successful session guitarist. The first and only album by this short-lived line-up has since achieved a certain cult status and is highly sought after by collectors worldwide.