In the spirit of Valentine's Day, Meredith and Derek try tohave a night to themselves when Lexie offers to watch Zola;Callie hands babysitting duties over to Mark so that she cansurprise Arizona with a romantic evening; and Ben proves toBailey that he knows her better than she thinks. Meanwhile,the ER fills with romantics, including a 10-year-old girl whohas an allergic reaction to chocolates from her valentine and aman who is hit by a car while chasing down his frustratedgirlfriend.