Memory Alpha says: Sisko falls in love with a woman visiting the station, but she is not what she appears to be. (Please click the Memory Alpha link for detailed information.)
I find this episode awfully dull. It’s an attempt to start building some more personality for Sisko, who I also find awfully dull at this stage, but I’m not best pleased about the fact that they chose to do this by repurposing a story designed for Julian (and which would make much more sense for someone as naïve and romantic as Julian was at this stage). Sisko’s personality is best revealed by the way he deals with big, commanding-officery problems, not by a rather drippy love story.