A famous columnist is murdered while Rosemary and Laura rid a hotel's vineyard of pestering weeds. Strapped for cash with no land-rover, the gardeners pull out all the stops in an attempt to kill the weeds without breaking their backs.
An old flame of Rosemary's, a noted scholar of Spanish Islamic history, contracts with the girls to help him restore an old Moorish garden on his estate in Spain but murder and suicide prove to be distractions.
Rosemary and Laura work on re-planting the historic Regent's Park garden, filled with its colorful flowers and an array of permanent visitors. But hidden amongst these frequenters of the park are many secrets soon to be revealed, all mysteriously connected to a three-legged dog.
Rosemary and Laura and Laura's son Matthew head to Spain where Matthew will participate in a tennis competition while Rosemary and Laura create a trophy garden. In the midst of their trip, a fellow tennis player is murdered leaving the gardeners with a mystery to solve.