Arrow season 8's premiere destroyed Earth-2, but The Flash set it up! 1 / 7
The Monitor sent Oliver Queen to Earth-2 to retrieve dwarf star technology. 2 / 7
But an antimatter wave completely destroyed Earth-2, killing (almost) everyone. 3 / 7
But on The Flash, Jay Garrick's Multiverse map showed the antimatter headed for Earth-2. 4 / 7
Still, The Flash didn't warn his friends on Earth-2 that the antimatter wave was coming. 5 / 7
It means that Harrison Wells, Jesse Quick, and probably died at the end of Arrow. 6 / 7
With Earth-2 wiped off the map, the stakes for Crisis On Infinite Earths are now raised even higher. 7 / 7