Never Say Genius by Dan Gutman
It is hard enough to be a twin, but these twins first names are Pepsi and Coke. Their last name is McDonald. These two thirteen year-old children are smart. They make a cross-country trip to Washington D. C. for their aunt's wedding. They make all these side trips for their mother's blog. Would you believe there is a museum just for mustard? Their parents don't know that the twins are being stalked. Their parents don't believe them when they tell them what happens.
The book has interesting codes (which I couldn't figure out). I was not familiar with Pigpen grid, Ogham alphabet or half-reversed alphabet. These clues mean something and they are deciphered. Do you agree with me that the google maps were used too much? Am I wrong or did Dan Gutman promise that two of the characters would save them by the end of the book? Yes, the third in the series will be published soon. Look for You Only Die Twice.