I like the characters you have going in that bit but you will definitely need a plot that can support a book.

Here are a couple questions that might help.

If you take these two characters who will become your main? Even in a story that has two prominent character one is typically still the focus with the other being a catalyst.

In your main character what needs to change? What part of them has to change for them to be a better/different person?

What kind of outcome do you want for your story? Do you want something with a happy ending or maybe something tragic but cathartic for the reader?

What do you want the reader to take away? Is your story a light/bubblegum story or is it a gut wrenching one?

Who or what is your antagonist? Are they people from the outside? Is it self-doubt? Maybe you have characters from their past coming back to haunt them.

I could keep coming up with questions like these but until you start coming up with answers that will cause more questions my questions wont' be too targeted. Gotta find those loose threads and pick at them.

Also, don't go for the obvious. When you ask a question try and go with your second answer for it. Example: when you answer that your character is rising from the ashes definitely don't give them a phoenix tattoo. Ask a second time what kind of tattoo they would need. You might be surprised that it's a mountain grew up near instead, or maybe it's the flame that burned them and not the phoenix they are going to become.

Take that all as advice. I don't mean to change your direction if you already have one. I just want to see a story that surprises the reader. Give it some punch. You can do it.

Jedi Moose

** General disclaimer: I am just a Moose. What do mooseseses know about writing stories??