Hello, Katerina! Yes, the Tidal Series and its main story arc with Carter and Riley will be complete with the two books, Wake and Calm. However, my cowriter and I are planning to explore several of the secondary characters of the Tidalverse in other books as they are very, very active in our imaginations. They’re basically demanding to be heard and we’re happy to listen!
I hope you understand why I can’t definitively answer your second question as it feels a bit spoilery 🙂 I will say, though, that both Carter and Riley are committed to rebuilding not only their friendship, but themselves. From there, they really can do anything together.
Thank so much for reading!