WHAT-IS: "Tokyo Ghoul: Jack (東京喰種［JACK］), is a Japanese manga published digitally by Shueisha in Jump Live digital magazine. It is a spin-off prequel story to Tokyo Ghoul (manga)."
PLOT: "The story is centered around the character Kishou Arima, who is a High School student by day and a ghoul investigator by night. The story is also set in and revolves around the 13th ward." (tokyoghoul.wikia.com)
Tokyo Ghoul: Jack is an OVA produced by Studio Pierrot based on the manga of the same name, with the story focuing on the high school days of Kishou Arima, the CCG's shinigami. Scheduled for a release on September 30th, 2015, I had excitedly watched the preview first without finding out about the show … with my thirst unquenched for Tokyo Ghoul, I was ready to lap this up! … "was" being the operative word … here are some instagrammed screensnaps for you :)
OVA PLOT: "In Tokyo Ghoul: Jack, an incident involving a human-devouring Ghoul occurs in Tokyo's 13th Ward. To seek the truth behind what happened to his friend, the rebellious high school boy Taishi Fura pursues the Ghoul named Lantern with the young ace investigator Kishō Arima. The story follows how the ace investigator Arima and the talented 7th Ward investigator Taishi Fura first met." (www.animenewsnetwork.com)