It's basically like Sailor Moon if Usagi had remained the only senshi. She defeats baddies from the Dark Kingdom, fights regular crime on top of that, uses the command center beneath the arcade, and eventually gets involved with the police. She doesn't remember her past life until the very last chapter, when she defeats Kaito Ace (AKA Adonis, from Venus).
I'd have to look it up to see if she continues what she does before she meets up with the rest of the sailor senshi in Sailor Moon, but when she meets them she pretends to be the princess.
Another thing to know, in case you don't know, is that she primarily used a
crescent-shaped compact mirror for her attacks (though it shouldn't hurt anything to add the chain). It also functioned like the disguise pen does. It's also the only item I know of that is explicitly said to require recharging (via moonlight).