02x24

We all go through life like bulls in a china shop. A chip here, a crack there. Doing damage to ourselves, to other people. The problem is trying to figure out how to control the damage we’ve done, or that’s been done to us. Sometimes the damage catches us by surprise. Sometimes we think we can fix the damage. And sometimes the damage is something we can’t even see. We’re all damaged, it seems. Some of us, more than others. We carry the damage with us from childhood, then as grownups, we give as good as we get. Ultimately, we all do damage. And then, we set about the business of fixing whatever we can.
—  Meredith Grey
7

In a Deadly Game Castle and Beckett struggle inwardly with their feelings for one another, even though Beckett is officially dating Demming and Castle is severely behind in his writing for the second Nikki Heat book.

After receiving advice from family and friends, both come to separate decisions that could make or break their relationship in the future.

However, Castle’s decision to leave for the summer with Gina is the end of a series of defeats for Castle in trying to get together with Beckett.

Two episodes before, in Food to Die For, Beckett had told Castle (speaking about the love triangle in the case) that given the choice of a man she felt real passion for, but suspected would be unreliable, she would pick the safer man who wouldn’t break her heart, an answer Castle took as a reference to Demming.

In the previous episode Overkill, Castle tried to compete with Demming in crime-fighting. During the B-plot to this episode, Martha (talking about herself) tells Castle that sometimes he has to be able to know when he’s been beaten. Castle clearly sees that this might apply to himself. While neither man wins, the episode ends when Castle catches sight of Demming and Beckett making out in the hallway. This also foreshadows the end of this episode, where Castle believes Demming has won, but neither man ends up with Beckett.

In this episode, Castle invites Beckett to the Hamptons. Beckett refuses, claiming that she’s out of vacation days and will be working. Later, Castle discovers that she lied to him. She instead intends to spend the weekend on the Jersey Shore with Demming.

As for Beckett, she decides to dump Demming and to tell Castle her feelings towards him but she stopped when Gina came into the 12th. Castle doesn’t find out that Beckett has broken off her relationship with Demming until the premiere of Season Three (several months later) and never appears to discover that she’d dumped Demming before Castle left.

A Deadly Game ??? Well, I would rather say a Deadly Break for both the audience and Caskett’s relationship.