Book on the Isle (Parallel Society, #2)

With a year in the Parallel Society under her belt, Veronica "Roni" Rider still feels like an outsider. Relegated to the basement library, she seeks some way to assert herself and find her place. Her chance arrives when she is sent on a mission into the Infinity Caverns to locate mystical stones in a lost universe. But the journey unearths many of the team's secrets, and the pressures upon them threaten to destroy their fragile group.

Then they discover the hellspiders and all bets are off.