Charisma Carpenter guest stars as Serena Lockner, a former high school classmate of Kate's who comes to her looking for relationship advice. Kate is hesitant to help her at first because of their history together, but in the end acquiesces after Serena convinces her that she is a changed person, genuinely interested in finding the right person. After one botched attempt and a bit of coaching, Kate sets Serena up with Michael and they, to Kate's surprise they seem to be hitting it off, that is until Kate and her chiropractor friend Dean go out with them on a double date and Serena's true colors are revealed. In the midst of all this, Kate is also embroiled in a nasty divorce proceeding involving a businessman whose wife is claiming that the pre-nuptial agreement they signed is void because he slept with the ^hot nanny.^ Although it seems at first like a pretty straightforward case, Nick charms some very valuable information out of the nanny, giving Kate and Jerry some inside information (thetvdb.com)