Suddenly, Amy has a revelation. She drags Dan off to the library.
In the library, they run into their uncle Alistair Oh, who wants to form an alliance with them.
They agree to it, because they'll need an adult chaperone if they plan to travel around the world. Dan says he hadn't been allowed to go on a field trip because he'd "put Mentos in his Spanish teacher's Diet Coke" (4.85). That sounds better than most field trips, if you ask us.
Amy can't find what she's looking for, and she wonders if there might be a secret library.
Faster than you can say "secret library," Dan pushes some buttons hidden on the Cahill family crest, and a bookcase swings away, revealing a secret staircase leading downward.