3.5 ish stars... 
 My favorite in this series is still the second book, which surprised me so much because I almost didn't continue the series after the first being a bit irksome for me. A pretty satisfying conclusion to the trilogy--I appreciate that like in book 2, there are some pretty big consequences and that the Aria-Perry relationship matured over the three books. Roar is definitely my favorite character, and there's a nice about of page time for him in this book, too. 
 Like the second book, I listened to the audio of Into the Still Blue, but I was disappointed it was a different narrator. This narrator has an older tone in her voice that took away from the youthfulness of the characters, especially Aria. It's kind of a bummer because the previous book's narrator nailed that tone perfectly. Still, the pacing of this series is great for audiobooking.