The Old Letter is a letter for Admiral Bobbery in Paper Mario: The Thousand-Year Door written by Scarlette on her deathbed. She would ask Podley to give this letter to Bobbery when she passed away though he never had it in him to give to Bobbery. Though he would give it to Mario to deliver.
 Contents of Letter
My love, if you are reading this letter, then I am no longer by your side. Because fate has stepped between us, I have decided to write you this letter. If you're reading this, I must have passed away while you were out to sea...I can only assume that you will blame yourself for it, my sweet Bobbery. Although my life was short, you gave me more than a lifetime's worth of joy. Though you will morn, I beg that you remember that time, like love, is a tide. You are one with the sea, as you were one with me. Do not lose both your life's loves.