The gardener's sin is my lord and lady's pleasure.

The daughter of an earl, Lady Mary Linden never noticed the servants who toiled on her father's estate. But her aristocratic blindness shatters when she meets Drake, the head gardener. Drake shows her sensuous delights she could not have dreamed of. Just when she thinks he has taught her all there is to know, Drake introduces a new player into their game...Mary's cousin Harry.

What they did was surely a sin...but a sin too delicious to give up.