Green Lantern v04 - Dark Days (2014)

Just as Hal Jordan, John Stewart and Guy Gardner are putting back together the Green Lantern Corps, lights across all of the different colored Corps begin to flicker. Lanterns from all over the universe begin to lose power, but unlike times' past, the reasons for the outage don't seem to be in-fighting between one another. Allying with enemies and friends alike, Hal links the answers to the mysterious alien Relic and their confrontations will leave all the corps forever changed.
GREEN LANTERN VOL. 4 begins a brand new era for the entire emotional spectrum, from writer Robert Venditti (X-O Manowar) and artist Billy Tan (New Avengers).
This volume collects GREEN LANTERN (2011-2015) #21-26, #23.1: Relic, GREEN LANTERN ANNUAL #2.