From the introduction:
On October 10, 2012 on the American cable network, The CW, a show based on the DC fictional universe came to television screens all across America and Canada. A fresh new take on a lesser known hero, the Green Arrow, the show was a hit to comic lovers and average viewer alike. The success of the show was enough to have its own spin off show, The Flash, which aired on the same network on October 7, 2014. The success of the two shows which share the same universe, and the crossovers between them have spawned Vixen & Legends of Tomorrow. Along with the canceled NBC show Constantine, this television network adaptation of the DC fictional-universe is dubbed 'Arrowverse'.
You arrive in your starting location when Oliver Queen arrives back in America after his presumed death. Alternatively you may start when Barry Allen, awakens from his coma. You'll be here for the next ten years, to help you on your journey here something has exited out of the Speed Force....