What to read after FRNK - Volume 4 - The Eruption?

Poor Frank. It's hard being a kid in today's world, but it's even harder being the only kid from modern times stuck in prehistoric times. He knows everything, but no one ever listens: not even when he's absolutely sure the volcano they're living under is going to erupt any day now, dooming them all to a fiery death. And why would anyone listen? Lava is so convenient for cooking meat and providing central heating. Of course, that's the moment baby Gargoyle decides to go missing. The search turns up old frenemies and new misunderstandings in the conclusion to the first arc of Frank's adventures.