Mysterious bypassed maiden races, beginning her career in the Group Three Cherry Hinton Stakes over six furlongs at the Newmarket July meeting.

[4] At Newmarket Mysterious was ridden as usual by Geoff Lewis and started at odds of 11/1 for the 1000 Guineas, with the Cheveley Park Stakes winner Jacinth being made odds-on favourite.

[8] Later that month Dahlia was a six length winner of Britain's most prestigious all-aged race, the King George VI and Queen Elizabeth Stakes.

In the Yorkshire Oaks in August, Mysterious won comfortably from Virunga, a French filly who had finished second to Dahlia in the Prix Saint-Alary.

She started odds-on favourite for the Sun Chariot Stakes but was beaten by Cheveley Princess, her only rival in a two-runner race.

[4] Mysterious spent her breeding career in the United States where she was bred to leading stallions including Northern Dancer, Mr. Prospector and Nijinsky.