Naval officer/ sleazy operator Nathan Forbes has succeeded in his scheme to marry fluttery heiress Millicent Collins, only to discover that Millicent has signed her vast fortune over to her little brother Daniel. Nathan comes up with a Plan B. Millicent is Daniel’s legal guardian, and he is Millicent’s husband. So if she is declared insane, he will be able to get his hands on the money.
From her first appearance, Millicent has been established as an extremely fragile person. So Nathan’s gaslighting project doesn’t take much work. She makes a remark in a calm voice, and he expresses dismay that she is so upset. Rather than dismiss this as a tiresomely dimwitted joke, Millicent becomes very agitated. She mentions that there is a light in a window across the way; Nathan denies that he sees it. Rather than wondering if his eyes are going bad, she is reduced to tears by the thought that she might be hallucinating. The whole process takes about three minutes. It’s fine for viewers who have been watching Millicent all along and know how precarious her mental balance is, but people tuning into Dark Shadows for the first time would probably think the scene was pretty silly.
Dark Shadows Commentary 