Horatio mobilizes top-priority after an explosive drug-lab releases killer fumes in one of the houses rented from Dr. James Welmont's dermatologists' consortium. The 'cook' messed up designing a new, hence technically under Florida law legal designer drug. The case also rekindles the tragic death of Horatio's cop brother. Eric investigates the murder of popular rest home-octogenarian Betty Rosen, whose skull was smashed.
A senior woman is found dead in her own blood-splattered apartment in a retirement community. Another case involves a body found inside an abandoned house used for cooking up recreational drugs.
- Horatio, Speed on scene of clandestine drug lab where a neighbor drops dead from the fumes in search for his pet. Horatio, Speed enter house wearing protective gear, using hand signals and in-gear-communication, find a neighbor, dead on the kitchen floor. They attempt to clean the same kitchen of deadly chemicals by bagging glassware.
Delko, Calleigh ready to process different scene where a senior citizen is found dead in her retirement-community home. They meet Det. Carrillo describing the scene as a massacre, with blood all over, leading to the victim; Alexx looks over the body, describing a fractured skull, and TOD around two AM. Calleigh, Delko take pictures, Delko lifts paper from a pool of blood near the body.
Exhaust fans are working at the drug house, Speed picking up bagged glassware putting it in buckets, all clear for explosion danger as the fans are working to clear fumes and Horatio gives an all clear to wheel out the body. Horatio finds a plastic glove which Speed bags and tags. Det. Sevilla found the owner, interrogated at HQ by Horatio. The meeting does not go well with the smug doctor explaining a group of dermatologists own a numbers of homes which are rented. The conversation with Horatio prompts the doctor to mention next time he will bring his lawyer, which Horatio adds, next time you might need one; a prophecy later to be proved true.
Alexx has the woman on the exam table reviewing with Delko her skull fracture, unable to identify the cause of the fracture, toxicology report showed blood thinner taken maybe explaining the blood pool size, and there were late stages of Alzheimer's based on tissue samples.
Speed, Horatio in lab, victim died from asphyxiation by nitric acid fumes, while they discover the formula was not followed to produce ecstasy, mistaking one ingredient for another, Horatio tells Speed we are chasing the cook, rather than Speed's the fumes or the pills.
Calleigh is interviewing Betty's sister Pearl who was out of town the night Betty was attacked; Pearl says everybody knew Betty was alone that evening, Betty could not keep a secret.
Horatio fumes the glove found at the house, identifying Gregory Kimble; Det. Sevilla adds the dermatologists use the type of glove that leaves no fingerprints. Det. Sevilla, Horatio interrogate Kimble, he asks for his attorney, having an upper-lip burn, possibly coming from mixing chemicals. Sevilla states to Kimble you drive a new Lexus, have no job, you are a student. Horatio demands his clothing be confiscated and Det. Sevilla pushes a jail-orange-jump-suit in front of him.
Delko meets returning trace employee Laura, inquiring about Betty, there was a recent sexual encounter, no sperm count, DNA to be checked. Delko ran a search for sex-offenders in the area, Keith Sewell. The convicted-rapist-gardener pulled in for interrogation, is abrasive, but provides DNA.
Speed, Horatio looking at Kimble's clothes, find chemical trace, but he is being discharged by the states attorney. Something about Horatio's brother is tied in with that attorney, as the confrontation escalates when the attorney leaves. Evidence not sufficient to hold Kimble per Florida statute.
Det. Sevilla, Horatio confront Kimble at a new house where he is unloading his cargo of chemicals, interrogated by Det. Sevilla and Horatio; Det. Sevilla gets a call a nineteen-year-old died from ecstasy. Delko, Calleigh interview all the senior men at her complex. Calleigh takes a ice-plant leaf from a suspect shoe and a swab for DNA.
Horatio, Alexx discuss the exam of the nineteen-year-old victim, Horatio takes a stomach fluid sample and Alexx searches for an undissolved pill for identification. She pulls a pill from the victim, showing it to Horatio with lettering on it. The lettering is from the target, dermatologist Welmont, but the weak-cook-Kimble is the ammunition to nail the target, per Horatio to Speed. On to Kimble's house they go.
Delko tells Calleigh there is so much gossip coming out at the complex that he doesn't know who to believe; Sewell, the sex offender is out as a suspect, alibi confirmed. Delko pulls the recovered piece of paper, processing it to reveal a letter from a law office confirming Betty's will was changed. Calleigh says Pearl did not kill her sister, Delko says somebody did.
Horatio, Det. Sevilla, Speed and an squad-officer are at Kimble's home, front door locked but Kimble is dead in the driveway vehicle. He was stabbed multiple times sitting in a vehicle with someone he knew. Horatio, Speed determine the murder was recent, bringing the vehicle to the lab for a look at what Speed cannot identify readily.
Calleigh, Delko are in Betty's bedroom, agreeing every drop of blood was Betty's, the also agree a string analysis to determine the point of origin. They walk through what they see, blunt force was at the counter-top, spatter going high, laying near creating a blood pool, got up and fell again hitting a table, got up moving down the hallway, spatter patterns around where she fell hitting another table making another pool of blood, spatter in the bedroom radiates in a complete circle, leaving no space for anyone else. Delko says all this blood indicates she laid there until she died.
Horatio, Delko review evidence from the vehicle seat. It is a bandage from a carcinoma removal, proved from imaging the doctor from behind, his attorney present and matching it to the image from the car seat. Horatio tells him catching your cancer has become your undoing. Det. Sevilla asks his attorney about his knife, saying we know he carries one for his protection. Sevilla inquires Did you bring your knife or did you lose it? Attorney adds the doctor has to travel to some dangerous neighborhoods to his properties. The lawyer produces the knife stating the doctor is cooperating all he can along this matter. Horatio quips how commendable. Sevilla doesn't believe the knife would be handed over with traces of blood on it. Horatio says he is not interested in the blood. Horatio has Speed take digital pictures at every angle and give it back asap.
Calleigh, Delko are telling Pearl her sister Betty died accidentally; she changed her will naming Pearl the sole beneficiary. Pearl accepts Betty's fate, repeating to Calleigh something she said before about Calleigh's hair being similar to Betty's, indicating Pearl is sadly losing it, too.
Horatio takes pictures of Kimble's stab wounds, he then has Speed match them to the pictures taken of Welmont's knife; the match proves Welmont killed Kimble. Horatio confronts the doctor, with his attorney, explaining the irony, had he not turned over the murder weapon, he could only be charged with negligent-homicide of the neighbor, but as it stands now, I can charge you with murder and I haven't even gotten to the nineteen-year-old who overdosed. Welmont smugly says so what are you saying and Horatio responds, thanks.