GUEST-STARRING BARRY ALLEN! Barry Allen is wanted dead or alive, but they'll have to get through Green Lantern first! As Hal continues his investigation into the mysterious (and deadly?) new chapter in the book of Oa, the trail leads to Central City and old pal Barry Allen! The boys in red and green team up to tackle a duo-mystery that will test their trust, their friendship, and the very life of the world's formerly fastest CSI investigator!