Dexter hires a nanny on episode three of season five. She seems to be great with Harrison.
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Dexter is actually a pretty good father to Harrison. We do worry about the lessons he may impart on his son, though.
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Dexter Season 5 Episode 3 Quotes

I'm just not used to checking the fridge for notes [Voice over]... just notes from other serial killers.

Dexter

True warriors are humble men.

Masuka