For Series 4 and Series 5, 'Whack The Mole!' was relaunched as 'Catch The Grand Mistress' to tie in with the new series. The objective was to locate and capture The Grand Mistress, the main antagonist of, "The Bunny Whisperer" and "The B Team".
Each week, missions would be unlocked and information would be released to allow the player to eliminate possible bases; which would result in the correct base being located by the end of the game through the process of elimination.
Various clues about The Grand Mistress' mistress plan were also scattered throughout the game.
For the new game, the graphics were modified and updated, but retained the same high-tech look. D.O.R.A. and the Spy-Pod were also present in the new game.
When a player completed the game, they would discover that her secret lair was located in the Kingsway Telephone Exchange and that her mistress plan was to build a particle accelerator to create everlasting batteries for her hypnotic children's toy, the Whoozle Top, not to create a black hole underneath London as the agents first thought.