Extreme bikers are racing through the park at night when one runs over something. When they stop to look what it is they see it is a body.
Alexis (played by Molly Quinn) is upset as she was charged with caring for her boyfriend’s pet rat and apparently she did not close the cage door well enough and it got out. She explains to Castle (played by Nathan Fillion) and grandmother (played by Susan Sullivan) that most rats only live to be three years old, but that this one is five years old. She feels so bad about losing him and starts looking everywhere in the apartment for him.
The victim’s name is Len Levitt. He was not robbed so that was not the motive. His driver’s license shows that he lived in Queens. He has never been married and has no family. In his pocket, they find a falcon feather.
Meanwhile, it is determined that the victim was shot three times with a 45 caliber pistol, once in the front from long range and twice in the back at close range. His wrists were also broken.
A search of the victim’s apartment leads the gang to wonder why it is full of electronic equipment and why there is a map on the wall with “BHS” on it. It is learned that Len changed light bulbs in the subway and was nicknamed “Light Bulb Len” by those who knew him. One of those people was not his supervisor, who could not recall ever having a personal conversation with Len in over 12 years.
A fellow worker tells Beckett (played by Stana Katic) and Castle that Len was an unsung hero. He designed the safety box that transit workers use that cuts the power so that changing bulbs is much safer. His co-worker had a theory that since Len had petitioned to have all the bulbs in the subway changed over to incandescent bulbs, thus leaving the city with thousands of regular bulbs in a warehouse that it only made sense he was killed as part of a cover up. It is learned that Len’s supervisor has been stealing the light bulbs and selling them.
They bring the supervisor in for questioning. After seeing an email he sent from a company computer, he admits to selling the bulbs to a buyer in Costa Rica for .20 cents a piece. He felt he was doing the city a favor because they would have only ended up in the landfill anyway. But he did not murder Len because when Len was killed he was packing up a shipment of light bulbs.
It comes to light that Byron Singer and Len had a friendly rivalry regarding a pair of red tailed hawks living in the park. He lent Len a camera to take pictures of the birds as proof of their existence since Len did not believe they lived there. Beckett realizes they did not find a camera at the crime scene and go back to look for one and sure enough they find it hanging from a branch of a nearby tree.
Once the pictures are developed it unfolds that a child abduction has taken place and Len had taken pictures of it while he was in the park. Now it was clear that the abductor killed Len when he saw him taking pictures. The abduction took place somewhere around 5:12 pm and the victim was a 10 to 12 year old boy who had been playing soccer in the park. It is learned that the boy’s name is Tyler Donegal and that his parents are divorced. His mother did not know Tyler was missing which leads the suspicion to fall on the father.
Castle remembers a time when he was shopping and he turned away for a moment and Alexis was gone. You can see the fear in his face all these years later. Luckily, she had just gotten bored and decided to take a nap under a rack of clothes but Castle was visibly shaken.
They find the father and confirm that the boy was kidnapped but the father is the one trying to get him back. His gun checks out to be the wrong kind and is cleared of killing Len. He was given a burner phone by the kidnappers and told to wait and to not call the cops. He shows Beckett and Castle a proof of life video of his son on the phone. In the message, the son asks his dad to be sure to feed Ace.
Turns out that the boy does not have any pets and after some investigating it is learned that ACE has to do with a system at the subway. Beckett and Castle figure out where the boy is and use Len’s box to turn off the lights to save the boy. Boy and father are reunited.
It turns out that the kidnappers wanted the boy’s father’s access to an elevator. They were former bonds traders, ex-Wall Street employees, who wanted to take some financial files only and needed access to secure elevator that required a key. The boy’s father had one such key and so they kidnapped the boy to gain access.
At the end of the day, Len not only caught his own killer but he saved a boy he never met.
After telling her boyfriend that she lost the rat, Alexis’ boyfriend explains that he is sad about it but that she is much more important. With that Gram screams and the rat is found.
This episode was written by Matt Pyken and directed by Bryan Spicer. Be sure to catch Castle on ABC Monday nights at 10 pm.