San Francisco Legacy House - Derek's bedroom
It is night, and a thunderstorm is lighting up Derek's room. He is sleeping (in striped PJs, by the way) and is dreaming. He is seeing images of a man underwater calling to him saying "It's coming, Derek". He is awakened by the sound of the telephone ringing, and when he answers it, the voice on the other end says Derek! You must help me. You must watch out." Derek realizes that it is his old friend Spencer Croft. The call cuts off, and Derek goes to his office to try and call his friend back. He connects with his friend's wife Serena, and she tells him that her husband was killed the day before.
San Francisco Legacy House - the next day
Over breakfast, Alex and Nick are discussing the events of the night before. Alex is telling Nick that Croft was Derek's roommate at Oxford and that William Sloan was the proctor just across the hall. Derek enters the room and admits to not getting much sleep the night before. Nick tells him that there is no record of Croft's telephone call either in the telephone company's records or in their own house telephone records (all in-coming and out-going telephone calls to the house are logged). Nick suggests that Derek merely had a nightmare. Derek refuses to accept that explanation and insists that Croft telephoned him.
Derek talks via video-phone to Sloan about Croft's death. Sloan tells him that Croft was found fully clothed floating in the wading pool in the garden behind his home. Derek is skeptical about a full grown man drowning in a reflecting pond. Sloan tells him that he is going to the memorial service in Montreal regardless of the bad history between him and Croft.
Rachel arrives to give Derek her condolances. Derek tells her that the last time he saw Croft was on a dig in the Middle East about eight or nine years ago. Croft had brought Serena with him. He tells her that they had made some important discoveries, and that Croft insisted on publishing their findings while omitting Derek's name. Croft and Serena were married soon after. He says that their friendship was never the same after that.
Montreal - Spencer Croft's Memorial Service
Serena Croft is speaking at the memorial service. She tells them that he loved teaching at the university in Montreal and says that his decision to teach was one of the few things he never questioned (although he questioned everything else). She begins to cry as the service ends. Serena thanks Derek and Sloan for coming to the service (**continuity alert** Notice the disappearing/reappearing wetness on the shoulders of Derek's coat). Serena tells them that they have all made mistakes and let too much time pass, and that Croft had believed that too. They are interrupted by James Donlon, who is the associate professor of classics at the university. He tells Serena that he will has the keys to Croft's office and that he will help her clean out Croft's things. He also tells her that he is happy to see how well she seems to be looking, and how it is a shame that Croft didn't live to see her doing so well.
After he leaves, Serena tells Derek and Sloan that she despises Donlon because he was always trying jockey for promotion and was always poking his nose into Croft's affairs. Sloan offers to handle cleaning out Croft's office, and Serena gratefully accepts. He tells her that he is in Montreal overseeing some "re-structuring" (Hmmmm, something tells me that it involves the Montreal House problems from "Ransom"). She asks them if they will be staying at the Legacy House in Montreal, and both Sloan and Derek are surprised to learn that she knows about the Legacy. She tells him that Croft believed strongly in their work, and that sometimes she believed that Croft regretted not joining the Legacy. Since Sloan is staying at the Montreal House, Serena offers to let Derek stay at her home. He accepts and asks if he can take a look at what Croft was working on at the time of his death.
Montreal - Croft's Office in his Home
Serena tells Derek that Croft's office was his inner sanctum, and that he was always the happiest when he was working on some ancient puzzle. Derek looks at Croft's notes and recognizes the language as a code that he, Croft and Sloan invented in college. He tells her that it will take a while, but that he thinks he can translate the notes. Derek and Serena continue to reminesce about Croft and how absent-minded he was. She tells Derek that Croft was a very proud man and that he regretted never seeing him and Sloan.
Later, Derek has fallen asleep while working on the translation of Croft's notes. In his dream, he once again sees Croft underwater calling out ot him. He awakens and is sure that Croft is trying to tell him somthing.
Montreal - the next day
Derek is on the telephone with Nick in San Francisco asking him to look in his things for an old book from his college days that might contain the key to Croft's secret code.
Later, Derek and Serena are walking in the garden. She tells him that she was recently very ill, but that they doctors obviously mis-diagnosed her since she is now fine. She shows him the reflecting pond, which Croft had built immediately after he returned from his last trip to Greece - he brought the materials with him from his trip. The pool is rather small and triangular shaped with large stones anchoring the three corners. Derek tells her that the large corner stones are lodestones - a form of iron-oxide used in ancient times for their magnetic properties. Derek notes that the pool is only a few feet deep, and reaches his hand into the water. At that point, he has a vision of something reaching up from the water to grab him. Shaking off the vision, Derek realizes that Serena has nearly fainted, and is sitting weakly on the ground.
Montreal - Croft's office at the university
Sloan arrives and meets Croft's secretary Monica, who shows him into Croft's office. Mr. Donlon is in the office going through Croft's papers. ( it's interesting that Donlon offers Sloan his hand and Sloan doesn't shake it.) Sloan looks around and notices that Croft's desk is the one that he and Derek gave Croft years ago to keep his papers organized. Sloan continues to look around Croft's office, and notices that a lot of his books relate to death. Donlon tells him that Croft was fixated on the subject of necrology. Donlon tells Sloan that Serena had ALS and that Croft's obsession began about the time that Serena was diagnosed with the fatal disease. Donlon also tells Sloan that a few months ago Serena was deathly ill, and the fact that now her husband is dead is more than mere coincidence. Sloan asks Donlon why he is so interested in Serena's health, but Donlon tells Sloan that he is merely curious.
Montreal - Croft's home
Serena gives Derek a package containing his college book that Nick has sent him from San Francisco. He tells her that now he is sure he'll be able to break Croft's code. Serena looks at the pond and sees it bubbling up - she then has a vision of a figure rising up out of the water. When Derek looks, the water is still.
That evening, Sloan and Derek are talking in his office, wondering about Croft's secrecy. Sloan tells him that Donlon was checking out Croft's desk, and Derek reminds him that Croft's desk had a hidden compartment. Sloan asks Derek if he knews that Serena had ALS, and Derek is shocked to think that Serena was seriously ill because she looks so radiant now. Sloan gives Derek a warning about becoming involved with Serena, and Derek assures him that they are just friends.
That night, Serena is dreaming about Croft carrying her out of the reflecting pond. He tells her to trust him and that everything will be all right and begins chanting in a foreign language. Serena sees a form rise out of the pool and pull her husband back under the water. Derek and Sloan hear Serena screaming from her nightmare, and rush to comfort her.
Montreal - the next day
Sloan arrives at the university, and charms the secretary Monica into letting him into Croft's office. In the office, Sloan looks in the hidden compartment in Croft's desk and finds a paper with a drawing of the reflecting pond drawn on it. Monica sees him take the drawing as he is leaving, and mentions it to Donlon when he returns later. Donlon is very upset by the news, but tries to cover up how important he thinks it is.
Derek and Serena are overseeing the draining of the reflecting pond. Derek is urging her to tell him what happened the night Croft died. She is very vague and tells him that she was ill in bed when Croft drowned. She tells him that that evening she had a dream that she was the one who died - not Croft.
San Francisco Legacy House
Nick, Rachel and Alex are tele-conferencing with Sloan regarding the reflecting pond. Nick tells Sloan that the measurements on the drawing were measured in ancient units that are no longer used.. Alex tells Sloan that the writing on the drawing is in an ancient Macedonian dialect of Greek. She says that she believes that the writing refers to a secret passageway or supernatural gate.
Sloan tells them that he doesn't believe that Croft drowned accidently. They wonder if Croft's words "Watch out for Serena" mean to "beware" or to "protect" her. Sloan pumps Rachel for information on ALS, and asks her about whether it is reversal, which she says is not possible.
Montreal - that evening
The pond refills itself with water.
Serena is sitting awake in her bed, and Derek checks on her to see why she isn't asleep. He tries to turn off the lights, but she will not let him saying that she is afraid of the dark. He asks her about her disease, and she admits that she was diagnosed with ALS, but insists that the doctors must have been wrong. Obviously upset, she lays down and asks Derek to leave.
Outside, Donlon is checking out the reflecting pond. He ventures too close, and a hand reaches out and pulls him in.
San Francisco Legacy House - the next morning
Once again in a teleconference, Nick and Alex tell Sloan that the pond is an exact replica of a pool that Alexander built so that he could escape death. Nick tells him that the lord of the underworld posted a sentry at the 'gate' so that no one could return. Sloan tells them that they did a great job, but Nick and Alex aren't quite sure if he actually complimented them (apparently, Sloan doesn't hand out compliments very often!).
Montreal - Croft's house
Derek tells Sloan that Croft's journal says that he knew Serena was dying, and that he tried everything to save her. Sloan tells him that the reflecting pond is actually a portal to the underworld. Serena finds Donlon floating in the pond, and begins screaming. Sloan checks out the pool while Derek comforts Serena (lucky woman!).
Sloan handles the police for Serena, and he and Derek try to figure out what to do. That night (it's a full moon), Serena looks out of her window to see the 'sentry' calling her back to the reflecting pool. She slowly walks down to the pond.
Derek finishes translating Croft's journal which says that he indeed planned to bring Serena back from the dead. Sloan calls it a "fool's errand", but Derek considers it 'noble'. Croft's journal begs the reader to destroy the reflecting pond by removing any one of the corner stones.
Outside in the rain, Serena is drawn to the pool. Derek and Sloan see the sentry trying to pull her into the pool, but Sloan pulls Serena back and Derek is pulled in instead. Derek battles the sentry while Sloan tries to remove one of the corner stones. Apparently, the sentry doesn't care who he takes as long as he takes somebody, and pulls Derek under the water. Derek frees himself, and climbs out of the pool just as Sloan removes the corner stone - closing the portal.
Later that night, Serena is finally able to turn off the lights and get some rest. She realizes that Croft is dead because he saved her.
Derek is writing in his journal.