Whos up for a history lesson, a twisty mystery, and a totally boss Bishop leg-sweep?

If so, youve come to the right place this week.

Its spring cleaning time at NCIS, and Bishop is going all out.

NCIS

Credit: Eddy Chen/CBS

But charity donations arent driving the case of the week.

The first person to attract NCIS attention is Det.

John Fischer, who investigated the unsolved murder of Noah and Claires parents 10 years ago.

Hes overall cagey and hostile with NCIS and claims not to know where Claires hiding.

But Fischer might be on to something.

So do we have a copycat, or is the original killer back?

Noah moved in to keep an eye on her, but she dragged him down too.

Next stop: the old ODonnell house, where the murders happened a decade ago.

(Rule 35: Always watch the watchers!)

In the backyard, they find a storage shed with a padlock that has Claires initials on it.

And yes, one of the dollhouses showcases Claires own parents murder.

Three of the dollhouses feature solved crimes, with the ODonnell murder the only unsolved one.

Sloane wonders aloud if Claires a hobbyist coping with trauma through true crime.

Ah, but tonight she has a new crime scene to visit.

Vance, seeing a traumatized young woman who lost her parents, scampers off to call his kids.

Claire starts things off by asking Gibbs, Has anyone you love ever been killed?

Then she says Noah was helping her solve their parents murders and mustve uncovered something.

Hes dead because of me.

Time for a new suspect.

At this point, Fischer storms NCIS, demanding to know why Claires being held.

That last one stops Claire short.

Weve been looking into the wrong case, Gibbs realizes.

If Noah started to suspect murder, that points in a whole different direction.

Paul realizes the jig is up and tries to run, charging directly at Bishop.

Its … its impressive.

Claire declines but mentions that someone recently offered her $10,000 to build their daughter a dollhouse.

OOOH, DO THAT, CLAIRE!