It’s Prodigal, chapter 7 in Detective 680 (Dec. 94), by Dixon, Weeks, Nolan and Rubenstein.
Two-Face has captured Harvey Kent, who was meant to be released instead of him, feeling that there is some weird bond between them. Two-Face is written to be quite irrational in this storyline, which works.
Tim consults Barbara Gordon, making her first appearance as Oracle in this book. Not yet as confident as she would become in Birds of Prey,the information she gives Tim in this story simply sends him right into the hands of Two-Face.
Shotgun Smith makes one of his rare appearances, as the Cluemaster and Czonk try an escape while being transferred. Dick proves more than adequate at stopping the two.
Dick also manages to free Robin and Harvey Kent from the double death trap Two-Face puts them in, though Dent himself gets away.
The story continues in the next issue of Robin.