What was Grovers last quest?

Grover Underwood's last quest, as depicted in Rick Riordan's "The Trials of Apollo" series, involved assisting Apollo and his friends in their mission to restore the Oracles and confront various threats. Grover plays a crucial role in helping to protect the environment and the spirits of nature during their adventures. His connection to nature and the wild is a key element of his character throughout the series.