Nightwing [Dick Grayson]; Carol Bermingham (death); Barbara Gordon [Oracle] (hallucination); John Grayson (hallucination); Mary Grayson (hallucination); Two-Face [Harvey Dent] (villain); Joker (villain; hallucination); Penguin [Oswald Cobblepot] (villain; hallucination); Mr. Freeze [Victor Fries] (villain; hallucination); Killer Croc [Waylon Jones] (villain; hallucination); Scarecrow [Jonathan Crane] (villain; hallucination); Poison Ivy [Pamela Isley] (villain; hallucination)
Synopsis:
"With Batman missing in action, Nightwing faces off against The Dark Knight's most dangerous enemies - Killer Croc, Penguin, Mr. Freeze, Poison Ivy, Two-Face and The Joker - to save the life of a woman marked for death." [per solicitation]
Dan Didio talks about the villains taking over the DC books in January 2009. Hot list - Detective Comics #849, Supergirl #34 and Terror Titans #1. House ad for Nightwing #150.