Following events on "Chemistry," Dexter is officially sleeping with the enemy. Deb's enemy, at least.

How will he react to his sister's missive on tonight's new episode?

Look for Dexter's attempt to keep his relationship with Hanna a secret to be compromised when he receives a surprisine visit from Astor, Cody and Harrison. Meanwhile, Isaak is out of jail and also hot on Dexter's trail, while Quinn continues to battle the Koshkas.

Watch the official Showtime teaser now:

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