An unexpected turn of events

Chapter four - the letters.

     The next day dawned bright and early. The sky was a brilliant, calming blue and the sun shone, as if nature itself knew what was about to happen. The three girls walked to school together, each one waiting for the other to speak. The first person to break the silence was Mary.
"So, what's up?" She asked, trying to start a conversation.
"Not much," Leah replied. She and Mary talked about books until they reached the school gates.
     You're quite quiet today, Jess," Mary remarked, as they walked inside, "Is everything all right?" They came to a halt in an empty corridor.
"Well," she began, "you know that box you told us about?"
"Yes?" Mary answered suspiciously. She could tell her friend had been up to something (no points for guessing what it was!)
"Well, I went out after dark to look for it and you won't believe what I found inside," she continued.
"What IS inside?" Mary asked curiously. (Leah was daydreaming at this point.)
"See for yourself, Jess responded, handing Mary the letters from her school bag. Mary read through the pieces of paper. By the time she had finished, she looked like she'd seen a ghost.
     "Why would he keep something like that from me?" She wondered out loud.
"Don't know," Leah shrugged.
"You could ask him now," Jess suggested. Mary turned around to see Owen approaching.
"Hey guys, how you doing?" He said. Leah and Jess didn't reply - it would spoil the plan. Instead, Mary quickly dragged Owen into a nearby cupboard.