Karyn goes to school

"Karyn," her mother called to her. "You better get to school." "Ok, Mom," she called back. She grabbed her stuff, including the stone, and headed out the door. When she got outside, and turned down the street, she almost fell over. At the same spot she would normally meet Jon, was standing Sarah McMillan. And as soon as Sarah noticed her, she smiled and waved! Mechanically, she kept walking until she caught up to Sarah. "Morning, sleepyhead," said Sarah, cheerfully. "What are you doing here?" asked an amazed Karyn, as they started walking. "Meeting you to walk to school, the same as we do every morning. What's so surprising about that?" "But... But..." Karyn sputtered. "You've always hated me." "What do you mean? We've been best friends since fourth grade. What's wrong with you?" Now Karyn was really confused. That was the same year Jon had moved here. What was going on?