A serial killer is stalking Gotham. But its victims are all juvenile delinquents, teens, and young adultswith criminal records and time served. Are they even worth saving? For Batman, the answer is alwaysyes. No matter who they are or what they've done, every life is worth preserving.Not everyone agrees with this sentiment, as Bruce Wayne will discover when an old family friend inviteshim to test a new longevity drug, Sangraal, something only the very rich will ever have access to. What'sSangraal's connection to these strange murders, and what's the price of immortality? Find out in thecritically acclaimed story "The Mercy of the Father" by dynamic duo Tom Taylor (Nightwing, Superman: Sonof Kal-El) and Mikel Janin (Batman and JSA)! Collects Detective Comics issues #1090-1096.