Lady Heather is back! The professional dominatrix who gets CSI's Gil Grissom all hot under the collar returns to the CBS series May 10. During this, her fourth stint on CSI, Melinda Clarke's character could very well shed some light on Grissom's secretive relationship with fellow CSI Sara Sidle. "He's a fascinating character to go after," Clarke teases. "And who doesn't love a good triangle?"

The writers are still working on a final draft of the script, so how Grissom resolves his personal issues and the problem of that pesky miniature killer in the season's second-to-last episode remain a mystery. - Reporting by Craig Tomashoff