Mouse was another band project – following Rock Workshop and Running Man – led by the legendary British prog-fusion and session guitarist Ray Russell. Together with keyboardist and singer Alan Clare, bassist Jeff Watts (Steel Mill) and Alan Rushton on drums, they recorded their debut album in 1973 at De Lane Lea Studios in London. Lady Killer was released in England in December of the same year on the recently established record label Sovereign, a short-lived subsidiary of the major label EMI.

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. 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.