CSI: NY

A Red Carpet event is disturbed by the arrival of a young woman, covered in blood and dirt. She collapses in the arms of her father. Flack tells Mac that the victim is Robin Prescott. She is barely conscious and came out of Central Park. Stella takes pictures of the victim and will make sure the clothes get to the lab to be processed. Danny has to handle all possible traces at the Museum.
Mac is called to another scene. Jordy Tompkins has been killed by a revolver shot to the abdomen. As Aiden and him study the corpse, they wonder about the wound as it doesn't seem consistent with gunshot.

After bagging the victim's clothes at the lab, Stella goes to Robin at the hospital to further their inquiry. She takes pictures, removes traces from a wound, scraps under her nails. The young woman doesn't remember what happened to her only hours before.
Back at the lab, Danny processes her clothing. He finds residues of different plants, which allow them to narrow down where the crime scene could have been. They check the map of the city to determine her journey through Central Park and find the only probably crime scene: north of Strawberry Fields, west of Ramble.

Hawkes gives his report about the gunshot victim to Mac. The man bled to death after being shot. The problem is that there was no bullet in his wound. The likely culprits are rats, as his body shows numerous bite marks.

Stella is at the crime scene in Central Park. She looks at the marks on the ground and takes pictures. She finds the victim's lost shoe, the discarded contents of her purse ,as well as a food container with a steak in it. Danny notes that there were possibly two aggressors, as two different sets of footprints can be found. Checking one of the prints more closely, they find a nose ring with traces of blood.

Aiden and Mac are searching the alley, in which Tompkins has been killed. They look for rodent activity and soon spot the building most likely to house the rats. Armed with a scanner to analyze metal residue, Mac checks the ceiling of a small market. The results indicate that the rat that ate the bullet is among the crowd. They need now to trap it.

The food container with the steak found in the park gives Danny and Stella a hint. The meat was marinated in coffee ground, an exclusive recipe from a four-star restaurant. It was probably taken by an employee as it was no left-over. When Stella and Flack go to the restaurant, they see that the guy washing the dishes has a bloody nose. They take him in for interrogation. Donovan Tracey tells them that he hadn't seen the victim, only her purse. When he tried to rob her, she grabbed him and he lost his nose ring. Not convinced, Stella asks for his boots and a DNA sample.

Meanwhile, Aiden and Mac ask for the help of Karl Drewdetski, a pest control employee to kill their rat. Stella questions Robin at the hospital to find out what she remembers. She can't say anything helpful as her memory is still failing her. Her father wants Stella to tell him as soon as they have any details. She can only say that their suspect probably only wanted to rob her. Back at NYPD, she gets bad news from Dr. Giles. The semen sample they retrieved from the victim had no sperm cells and therefore they have no DNA.

Aiden and Karl are using scrambled eggs to catch the rats. It works like charms as quickly the containers are full. But after scanning them, Aiden can't find the rat they were looking for. She goes back to the shop and checks the ceiling again. A dead rat lies there and the scanner tells her it's their culprit.

Danny is able to determine that there was linoleic acid on the victim's dress. It comes from walnut dust and this is used by the city to clean statues in the park. The day of the attack the four-men crew was working in Central Park but in a different location. It means that it was secondary transfer from the rapist to Robin. As they have no DNA from the sample, they can't do simple swabs. They have to get semen samples from the men. When the results come back, all four men are exonerated. They all have sperm cells. Stella is frustrated, as it means they missed something.

Mac and Aiden retrieve the bullet from the rat. They need to isolate the bite mark made by the rodent from striae made by the gun barrel on the bullet. Mac studies the rat's teeth, while Aiden gets bullets from different types of revolvers by shooting in a water tank.

Stella goes back to the park and studies the area where the statues are cleaned. She notices that flowers were freshly planted. Billy Rendish, the gardener, denies his implication and points out that he was at completely different location the whole day. He agreed to give a sperm sample to prove his good will. Stella asks for his working clothes and boots from that day. She is certain that they have the culprit, but they have no way to prove it beyond reasonable doubt. His sample showed no sperm cells like the rapist's, but a good attorney would get him out of trouble. Without DNA, they can't prove both samples came from the same person.
Stella goes back to the hospital. She tries to convince Robin, who is leaving the hospital, to accept to do a line-up. Only a positive ID can help them to convict the rapist. The young woman still doesn't remember a thing but finally agrees.

Aiden finds a match in IBIS for the bullet they retrieved from the rat. It matches a shooting, which took place earlier that evening in a deli. The man is still held in police custody. Mac goes to interrogate him. He shows Calvin Montgomery a picture of the victim. He denies knowing him. His agitation shows Mac that he is probably a drug addict. He thinks Calvin killed the drug dealer because he didn't sell him anything. Calvin denies it saying he threw the gun away and anyone could have killed Jordy. As Mac never gave him the dealer's name, they know he did it.

Robin is a no-show at the line-up and they have to let Billy go. Stella is once more frustrated. Mac tells her to trust the evidence. She decides to go through everything they have gathered from the victim and the gardener once more. Aiden, Danny and later Mac join her in her task. Mac notices that Danny has found tree sap on the victim's panties. Stella remarks that Robin had no traces of sap anywhere else on her. It is probably from secondary transfer. Rendish was working in the north of the park, cutting trees to deal with beetles infestation. They look for traces on his clothes and find some on his pants. Stella takes the panties and compares both stains: they are identical in color and form. They can finally arrest him.