Sword Art Online: Alicization Episode 4: Departure
Episode 4 of 24 of Sword Art Online: Alicization, aired October 27, 2018, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Kirito and Eugeo realize Selka has taken off to the End Mountains alone, and decide to chase after her. As they enter the cave, they encounter goblins, presumably from the Dark Territory, and must engage in a battle.