You won’t find a safe, complete, legal, free PDF of this book. Your best bet is to or rent the official e-book from Pearson. If you absolutely need a free resource, ask your teacher for a loaner copy or use OpenStax Calculus (a free, legal, high-quality alternative).
Here’s the straightforward answer, framed as a "story" as you requested, but with the essential information you need. calculus graphical numerical algebraic 4th edition pdf
I understand you're looking for the PDF. This is a popular textbook by Finney, Demana, Waits, and Kennedy, often used in high school AP Calculus courses. You won’t find a safe, complete, legal, free