“During the Free Play Event, you’ll get access to ESO’s base game and Morrowind DLC, allowing you to explore a massive world filled with beauty and adventure as you fight to restore the demi-god Vivec’s lost powers and reclaim your stolen soul from the Daedric Prince Molag Bal. In addition to this, ESO’s base game also includes access to Cyrodiil, a massive open-world PvP zone, and the Battlegrounds, a fast-paced 4v4v4 PvP arena. Even if you already own ESO but never acquired the Morrowind DLC or Chapter, you’ll be able to travel to Vvardenfell and experience the home of the Dark Elves during the event period.”
Brand-new ESO accounts rolled for the event will collect 500 cash-shop currency too, but if you’re not truly new, it sounds like you can still pick up where you left off last time: “Any characters and progression earned from previous trial events will remain, and if you decide to buy ESO after the event, you’ll be able to continue your adventures without interruption.”