In Too Deep by Jude Watson

"Is there something you want to tell me? About what you're really doing in Australia?"
"Okay, Dan said. "I guess it's time we told you the truth."
Amy gave him a no way look.
"Back in Massachusetts, Amy and I broke into our school one night. No biggie, right? Except that our assistant principal, Mortimer C. Murchinson, is an alien. At night he takes off his face and turns into this eleven-foot-tall thing with eight arms . . ."
". . .who plays for the Boston Celtics," Shep said with a sigh. "I get it." His gaze was searching as it rested on them. Then he turned and started back to the cockpit. "If you see any stealth bombers coming our way, just give a yell, okay?"
"You got it, Captain," Dan answered. (108)

In Jude Watson's second book for the 39 Clues series, In Too Deep is a very appropriate title. Dan and Amy Cahill are off to Australia, with au pair Nellie and cat in tow, and they are in over their heads. The Kabra's mother Isabel has entered the fray, and she is not happy with the way her children have been handling the hunt. Irina is also following close behind, but might have her own agenda. New things are coming to light about Nellie, including the fact that she can fly a plane?! New information is also resurfacing about Dan and Amy's parents, and the fire that took their lives. In the race for the 39 Clues, you either sink or swim.

AMY