The cover of Batman 363 (Sept. 83) proclaims the introduction of Nocturna, but in fact she, and the Thief of Night, had both debuted in the previous issue of Detective Comics.
Still, the pair are at the core of the Moench, Newton and Alcala story, and their combined origins are told in this issue.
Lucius Fox introduces Bruce Wayne to Natalia Knight at a party at Wayne Manor. Vicki Vale, already in a stressed relationship with Bruce, sees the two of them together and storms out. The Thief of Night bursts in, robbing the guests, which Jason Todd spots from the staircase (too young to join the party, but old enough to spy on it).
Batman already is aware that Nocturna and the Thief of Night are working together, and heads to Natalia Knight’s apartment. She does not even try to deny her involvement, but explains her impovershed past, and being taken in, adopted and trained by Charles Knight, a successful thief, until he was killed by gangsters.
After Batman leaves, we get the other part of the story, that the Thief of Night was Charles Knight’s son, Anton, who quickly fell in love with his “sister,” and turned to crime to support her.
Jason Todd attempts to force Batman into allowing him onto the case, as he has discovered where Nocturna and the Thief have their secret base. Batman is not at all impressed, but forces the boy to reveal his information, about their observatory.
Unhappy with everything, Jason sneaks away from Wayne Manor that night.
The story continues in the next issue of Detective.