In my mind, the first few chapters take place a few months before Elsa's accident with Anna when they were kids, and before Jack becomes a guardian. In later chapters, it directly corresponds with Frozen's storyline, but still before RotG. It is definitely spoiler filled, so I suggest you watch the movies first.
I'll also most likely go back every now and then and edit chapters I feel were lacking details or anything.
Another thing, I'm taking inspiration from some pieces of artwork/comics from tumblr or Instagram, so I'll be sure to give credit to those artists in the after comments.
Thank you! Hope you enjoy!