Sara and Nick are called in to investigate a possible murder in the house of a hoarder that was ordered to have a mandatory clean out. As the two CSIs slowly documented for evidence in the jam packed and rodent infested house Nick accidentally stepped into the decaying body of what they assumed was the house's owner.
While processing the house and waiting for the coroner to arrive to remove the body Sara and Greg (who had come to assist with processing the crime scene) discovered that they were not alone in the house. Mrs. Santiago, the owner of the house, was inside and revealed that the dead body belonged to that of her daughter.
While Mrs. Santiago was taken to the police station for further questioning Sara, Greg, and Nick continued to process the house and followed a blood trail they had found. Amid another pile in the house Greg discovered the skeletal remains of another body.
An examination of the remains by Dr. Robbins and Dr. Langston revealed that they were those of a young man in his teens. A test of some of the remaining bone marrow revealed a high dose of arsenic poisoning. Mrs. Santiago's case worker was called in to assist the CSIs process the house by breaking down Mrs. Santiago's stacking pattern. A quick look showed the case worker that something was amiss and one of the rooms in the house was found to be completely cleaned out. Sara made a disturbing find in the yard and three more male skeletal remains were unveiled in a similar condition as the first body.
The bodies of the young men found in the house turned out to be residents of a halfway house run by Mrs. Santiago's son. Further investigation of the house and the piles of totes lead to the discovery of the daughter, Alisa, handcuffed to a bed. Nick and Sarah clash over the true culprit behind the murders.
After a careful search of the house for the items used to kill the boys, Alisa, Mrs. Santiago's daughter, was revealed as the killer of the young men.