Police are called to the home of a murdered man, named Lawrence Jennings. Jennings' mistress says the man's wife shot him and then barricaded herself in the bathroom.

The police get the wife to come out of the bathroom. She looks at the mistress and says she was the one who shot the man.

All the evidence point to both women being guilty, or innocent. Both have GSR, which confirms their story that they both struggled for the gun.

A Navy lieutenant reveals that Jennings won a lottery last year, taking home about $500 grand in prize money after taxes.  That's when he met his mistress.

Bishop reveals that Jennings' wife went on a spending spree, going through all of the prize money and accumulating $40,000 in credit card debt. She says that in a rage, Jennings cut up his wife's credit card.

Tony reveals that the mistress too went on a shopping spree, only it was a medical one, where she got all kinds of cosmetic surgery done. Jennings cut her off too.

Gibbs decides to ask both of the women to take a polygraph.

Turns out Jennings shot himself because of their greed. The two women then conspired to make his death look like a murder so that they could split the insurance money. Had they not done so, the insurance policy would have been void, because of a clause that precludes payment in the event of a suicide.

Both women are charged with insurance fraud.

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The B-plot: Tony Senior is accosted on the street by a homeless woman who believes he's her father.

He decides to help her, but is worried that she appears ill.

Senior takes her to a homeless shelter, looking for medical help for her. One of the workers there agrees to let a physician's assistant take a look at her.

The assistant discovers that she's showing symptoms of dementia, which could be caused by a brain tumour.  He'd like her to get to a hospital but they don't know her name.

Senior goes to Abby with her fingerprints, and they discover her name is Susan Lowe, a former army corporal, honourably discharged years ago.

They also find out she left home years ago because her father got angry and couldn't accept that she is gay.

When they go back to the shelter, they find out she left.

Tony and his father finally hunt her down to a park bench. Senior feels her forehead and finds she's got a high fever. Tony calls for an ambulance.

Senior visits Susan in the hospital. The doctor tells him that her brain tumour is inoperable and that she has a month to live, or less. Senior decides to play along with her belief that he's her father. He apologizes for not accepting her all those years ago, and tells her he loves her. She smiles, happy to be reunited with him.