https://screenrant.com/percy-jackson-episode-5-lobster-war-grover-explained/

Percy Jackson season 1, episode 5 has viewers wondering, "What was the Lobster War?" in light of Grover’s shocking "praise" for Ares, the God of War.

What Happened When Ares & Grover Last Met Before Percy Jackson Episode 5 (https://screenrant.com/what-happened-ares-grover-last-meeting-percy-jackson-episode-5/)

The last time that Grover and Ares met before Percy Jackson episode 5 was the event that truly kickstarted the need for Percy's season 1 quest.