The main story has Karen telling Grace she doesn't like Leo. The best scene is where Karen plays tennis with Beverley Leslie (the always funny Leslie Jordan) against Grace and Leo - and Karen belts the ball over-and-over-again at Leo. Poor Leo is left clutching his crotch while Beverley shouts out 'take that you giant'! Also interesting is Grace pretending to be a rich Irish woman in Karen's exclusive club.
The other story has Will checking on his mother and finding her depressed about her broken marriage. Jack first suggests that Marilyn come with Will and Jack to 'Mama Mia' - which in turns leads to Jack suggesting that Marilyn shift in with Will. This is one of the few episodes that Jack actually uses his brains and it also leads to the story-arc with Will and Marilyn sharing the apartment and having some very hysterical stories in the future.