Henry stood outside his father’s office, a nervous hand hovering over the doorknob. He cracked the door open. Despite what his mother had said, he would not have been surprised to see his father sitting behind the desk. He inched it open wider, Spidey-Sense on full alert.

Not only was the office empty, but it looked as if it hadn’t been occupied in weeks. The window was closed, the desk was clear of papers, the chairs were in their usual spots. And yet …

He reached down to pick up a feather from the floor.

Henry had a new hideaway—a secluded, makeshift cave behind the garage that he made from a well-used picnic table, a stained painter’s drop cloth, and a variety of scrap wood and logs that were drying out to be used in the fireplace. The cave was easier to get to than the loft, and he’d designed it to look like a scrap heap of random materials so as not to draw attention to it. The average eight-year-old girl would never suspect it was anything more than a pile of discarded remnants from household projects.

He brought the feather from the office, along with his very best Audubon spotter’s guide. The detail in the book did not identify individual feathers, but he thought he might possibly get close by matching the colors of birds with those of the feather. Black and gray, maybe a little yellow?

He slammed the book shut in a huff. It seemed that almost every bird had black and gray feathers. And besides, what good would it do to identify a feather? How would that help solve the mystery of his father’s sudden appearance, and even more sudden disappearance?

He was reminded of the feather from the falcon. He scurried into the garage and up the pole to the loft, where he took the feather from the armoire. Back in his cave, he studied the feather carefully. Having seen the bird up close, he had more to go on, and he found what he was looking for in the section about falcons. Mostly because of the unique tail feathers and coloring, he identified it as an aplomado falcon. The pictures that featured its beautiful light-orange belly and head were stunning, but he appreciated them even more for having seen one in the flesh (or was that feather?).

Could the two feathers be from the same bird?

Neither of them was very long—so not from the wing or tail. While the colors were similar, the markings were definitely different. But how different? Placing a small rock over each of them to keep them from blowing away, he zipped up the pole again, retrieving a magnifying glass. It was a gift from his father—large, heavy, and powerful—that had been given to him on his seventh birthday.