Sword Art Online Alicization Episode 02 | Sword Art Online Wiki

A primary theme of the episode is the blur between reality and simulation.

Kirito awakens on the 19th Day of the 3rd Month of the Human Empire Calendar in a dazed state. His memories of the real world—including his final moments with Asuna—remain intact, which confuses him given that his previous dives into the Underworld involved memory suppression.

While exploring, Kirito finds a boy named Eugeo tasked with chopping down a massive tree known as the Gigas Cedar or "The Demon Tree".

Episode 2 of Sword Art Online: Alicization , titled "The Demon Tree," serves as the foundational "world-building" chapter for the Underworld arc. Picking up immediately after Kirito is attacked in the real world by Johnny Black, the episode shifts from the high-stakes tension of the series premiere to a slow-burn introduction of the new virtual reality.