On a beautiful, sunny day, something is not quite right at a quaint boarding house for pensioners. A seemingly kind old woman is the caretaker of a half dozen elderly people, but all is not what it seems. First, Stanley-a tenant-has abruptly left to live with relatives. Then when Mary, a childlike older woman, is asked to lead them all in prayer before the meal, she begins reciting the ominous Psalm 23 at the caretaker's encouragement.
Elsewhere, skeletal remains are found three feet down in a residential back yard. Da Vinci, Shannon, Leary and Chic are on the scene. Da Vinci surmises that the body had been there for a number of years, long before the current owner bought the house. Aside from the skeleton, there's a polyester shirt and a pacemaker-which can be traced for identification.
At the boarding house, we discover that the caretaker has a son-Burt. He's nearly as old as the other tenants, but much more physically able. His pet dog Plato shares his medicine when his mother leaves his room. Waiting was wise, as the caretaker has a violent temper. When Mary messes her bed, the caretaker literally throws the dirty linen at her in a rage.
Helen brings Da Vinci the latest on the body. The skeleton is identified through the pacemaker trace as a Robert Magus. The device was installed in 1990 and then recalled in 1994, so they estimate death sometime in between. A hunt begins for his social insurance number.
Magus was an elderly male suffering from osteoporosis. Sunny is able to find no evidence of a violent death. Another piece of the puzzle falls into place when it's revealed that Magus lived at the house when it was being used as a boarding home.
Burt is digging a fish pond and when his mother takes Mary out for a walk, she asks him to keep an eye on Alice and not let her get sunburned. Burt proves he's capable of following simple instructions because he does tend to Alice, but then gets upset with her when she tells him she doesn't like fish.
Sergeant Shelia Kurtz is giving Detective Angela Kozmo the missing prostitutes case that has been a thorn in the department's side for quite some time. Kurtz is about to call Shannon and Leary off the Magus case when another body is discovered at the same location. This one is female, buried naked, 60's or older and once again no foul play. The only thing they have to go on are missing filings and dental records.
The caretaker's scheme is being revealed as she has Mary sign some legal documents they picked up on their trip to the bank. Burt is kind enough to give Mary some violets in exchange for her social insurance checks and life savings.
Da Vinci is perplexed as conflicting information comes to light regarding Magus. Despite the pacemaker recall in '94, Magus was still collecting checks from the government until '96. They were sent to 1255 Baker Street, a run down derelict building that used to be a rooming house for pensioners until 1997. Leary arrives and tells Da Vinci and Shannon that a Viola McKnight ran the boarding house where Magus was found, but the name doesn't ring any bells.
When Chic arrives, he discovers that Da Vinci's hunch was right. Two more bodies are discovered in the backyard at 1255 Baker Street. Ruth Vera ran this boarding house from '93 to '97. This is no longer something that can be written off as isolated incidents or coincidences. Da Vinci and the rest of the team begin to suspect foul play, poison and a welfare scam. They suspect Viola McKnight and Ruth Vera are the same person, and the she's now either searching for a new ID or already using one.
The female body from 1255 Baker Street has some odd holes, originally thought to be bullet holes, but they're too uniform. Sunny id's them as Burr Holes, used to treat victims of head wounds when blood needs to be drained. Often people who suffer from epilepsy have this type of surgery. It's something to go on and Shannon and Leary eventually are able to ID this skeleton as that of Elizabeth Grass.
Back at the boarding house, Mary sneaks a pancake to Plato while the caretaker ushers the other boarders into the kitchen to clean up.
Da Vinci is berating some unsuspecting woman from social insurance about sending Robert Magus checks long after he died. The woman doesn't know what Da Vinci is talking about and says that she met the woman taking care of Magus-Viola McKnight- and had no reason to suspect anything was amiss. They stopped sending the checks after Viola told them that Magus had "Gone to live in a nice home in the country." Da Vinci is less than amused at how easy it was for Magus to simply disappear and Viola to get away with her scam.
Do the surprise of no one, despite her bones being in the morgue, Elizabeth Grass is supposedly alive and well in Vancouver. Shannon and Leary head to the boarding house and we finally learn that the caretaker is going by the name Elizabeth Grass. Shannon convinces Elizabeth to go down to the station for questioning as long as someone stays to keep an eye on her tenants. Shannon agrees, but second guesses his decision when Mary and Alice announce they want lunch.
Burt, who has been frantically searching for Plato, sees his mother being ushered into a police car and skulks off to the garage where he grabs a large chest and carts if off to the woods. There he tips it off the path into the brush where it is marginally hidden.
Leary questions Elizabeth/Viola/Ruth who dodges all questions and does a very convincing absentminded old lady routine. She's impossible to trip up because she tells them nothing and claims ignorance when it comes to all the strange findings at homes she used to own.
The skeletal remains are not offering up any cause of death, so Kurtz sends in Da Vinci. In his disarming, but intense way he questions Elizabeth further. She still offers nothing, but Da Vinci's insights into human behavior have him doubting her every word. There's no hard evidence to hold her on, though.
Back at the boarding house, Shannon meets Burt as he rushes in after disposing of the chest. Burt is looking for Plato. Shannon sends him on his way. A moment later an anguished scream echoes through the house.
Plato has been found.
Burt is in hysterics and Mary is heartbroken because Plato died after she fed him the pancake. Shannon calms down Burt and learns that he is Elizabeth's son. Burt reveals he's not supposed to talk to police because they'll "find out everything."
Da Vinci learns that Burt is Elizabeth's son and heads straight to the boarding house. Da Vinci works his magic on Burt and convinces him the best way to help Plato get to heaven is to either do an autopsy on the dog (which nearly causes Burt to go into hysterics again) or to reveal the details on how "the others" died. Burt offers up Stanley and shows Da Vinci where he dumped the chest.
Back at the station, Elizabeth is still giving Leary the run around, dodging questions about Ruth Vera and insisting she needs to get back to "protect" her tenants.
Burt is brought in for further questioning and Da Vinci plays up his 'not a cop' roll, convincing him to open up further. He tells Burt what he thinks happened, that all the people Burt 'helped to heaven' didn't really make it to heaven because they were poisoned. Burt doesn't understand how that would be possible because "they only ate what mom cooked."
The pieces of the puzzle have all fallen into place save for the elusive proof of Elizabeth/Viola/Ruth's guilt. Elizabeth tries to throw the blame onto Burt, saying he's troubled and "might have done something terrible." Da Vinci is almost openly disgusted with this woman. For her part, Elizabeth is great at her role. She only comes close to slipping up when she hisses at Da Vinci about how hard it is to survive in this society as an older person.
The entire team meets in the morgue to open the chest and discover Stanley's mummified body. The summer heat did wonders at preservation. They discuss how futile pursuing this case would be, even though Da Vinci balks at the idea of allowing Elizabeth to continue her scam on unsuspecting people. Burt would get put in a psych ward and no jury would convict Elizabeth without hard evidence.
Back at the boarding house, Elizabeth puts a "room for rent" sign up in her window.