In the book Words In Deep Blue, Rachel Sweetie (the main female character) placed a letter inside Henry Jones' (the main male character) book Prufrock and Other Observations.The letter states her love for Henry who is her best friend. Then she placed the book in the letter library at Howling Books so that Henry can read it. The significance of the letter library is that Henry and his family buy more secondhand books and place them in a separate section of the bookstore called The Letter Library. The Letter Library is there for people to comment on their favorite parts of the book and/or leave a letter to another person just as Rachel did. The letter that Rachel left in his book read:

Dear Henry, 

I'm leaving this letter on the same page as "The Love Song of J. Alfred Prufrock" because you love the poem, and I love you. I know you're out with Amy, but **** it---she doesn't love you, Henry. She loves herself, quite a bit, in fact. And I love you. I love that you read. I love that you love secondhand books. I love pretty much everything about you, and I've known you for ten years, so that's saying something. I leave tomorrow. Please call me when you get this, no matter how late.

Rachel

Henry never called Rachel about the letter, but he wrote letters to her when she moved. Rachel, heartbroken, replied with one sentence to his letters and then didn't reply at all. But the ironic part of this is Henry never replied to Rachel's letter because Amy (Henry's ex-girlfriend) kept Henry from being able to see the letter. Things got a lot tougher for Rachel when she lost her brother Cal in a freak accident. Cal drowned in the ocean, and ever since then, Rachel has never been the same. As for Henry, he has a lot on his plate as well. His mom and dad are divorced, his girlfriend Amy broke up with him to be with another guy, and his family is now in the process of selling Howling Book Shop, which is his home. Literally.

After Year 12 is over, Rachel's Aunt Rose finds her a job for the summer at the hospital that she works at and offers Rachel to come live with her. Rachel dreads moving back to her hometown, Gracetown, Melbourne, for fear that she will run into Henry, but that is an offer that she cannot refuse. Once in Gracetown, Rachel gets bad news from her Aunt Rose saying the job she had got Rachel fell through, but she got Rachel a job at Howling Books where her ex-best friend, ex-crush, lives and works. At first she refuses the job, but then accepts it.

As Rachel and Henry begin to work together, they start rekindling their friendship and spark up a new relationship that will bring them even closer.