Awesome! And my idea was that Cas would get a hotel room for him and Iris.
I had a little timeline of events:
1. Cas notices the way Miles is behaving around Iris and starts to worry that something happened between them while he was at the palace. This would also delay his initial plan to spend the night with her, because he would be uncertain about her feelings about him. He'd probably go a little over the top trying to win her affection back, to which she could notice and assure him that he doesn't need to earn it.
2. Cas would have to come clean about his relationship with Iris to Miles, so his friend would realize she's taken and stop trying to flirt with her. Miles isn't a douchebag, so he would back down as soon as he knows she isn't single like he'd thought.
3. Something happens between Cas and Atlas that pushes Cas over the edge. He leaves the palace in a rage, telling his father that he needs space. He goes to Miles' place to calm down, taking comfort with Iris and his friend(s). Losing respect for Atlas, this is when he decides to get a hotel room to spend the night with Iris. Instead of going home at midnight like he's supposed to, he stays out with her all night as a form of passive rebellion.
4. The next morning, he turns his phone back on to find a storm of missed texts and calls. While he was gone, Atlas had another severe episode, had been taken to the hospital to be treated, but didn't make it. He needs to report back to the palace immediately to be prepared for his coronation as the next king.
What do you think? ^^ I enjoy lots of action and drama, so I think it'll be good. I don't have much for Iris's side, but I figured you can find some ways to fill in the gaps. Maybe even give some updates on Ethan's side while she's still stuck with Miles?