Directed by Creator/DavidPlatt

Written by Creator/NickSantora

Dozens of people are injured when a ferry crashes into a dock, and a woman named Donna [=McLean=] is thrown overboard and drowns. When a witness suggests Donna was in the water ''before'' the crash, Green and Briscoe investigate whether she was pushed. Donna's first husband was a firefighter who died on 9/11, and she's now re-married to his best friend Ed [=McLean=]; who left his previous wife Collette for Donna. A suspicious arm fracture strongly suggests Collette pushed Donna, so Collette is charged with murder.

[=McCoy=] has the detectives trick Collette into licking an envelope so they can obtain a DNA sample, and it proves she was on the ferry. It's then discovered that a week before Donna was killed, Ed filed for full custody of his children with Collette on the grounds that she was not mentally stable enough to care for them. Her defence claims she suffers from PTSD because of the effects of 9/11 on her family and community, and she was not responsible for her actions when she killed Donna.

[=McCoy=] won't agree to a plea because Collette has left Donna's children as orphans. At trial he points out that Collette lied to police and covered her tracks after the murder, and she hasn't tried to get any help for her mental health despite being insured. Furthermore that Ed, who can no longer work as a result of trauma from 9/11, is more severely impacted by PTSD than she but hasn't tried to kill anyone. The jury convicts although Southerlyn feels [=McCoy=] was unnecessarily harsh toward Collette.

!!Tropes for the episode:

* AmicableExes: Collette Connolly tried to convince Fontana and Green that she and her former husband Ed [=McLean=] were this, although the truth reveals that they were anything but.
* AssholeVictim: Implied with Donna and Ed; they fell in love and left Collette, their best friend and high-school sweetheart, respectively, high and dry and forced her to go to work to support their children (after previously being a {{Housewife}}), he was barely paying her minimum child support, she couldn't contest him for it since all the money was in her name (which she willingly did) and then they tried to take said children away [[NeverMyFault due to being left a wreck after both the attacks and their actions.]] Plus, she's also hinted at being a GoldDigger and a RichBitch who even cut off her old friends from her former neighborhood and has no remorse over what she's done.
* BigFancyHouse: With the millions that Donna received from the 9/11 payoff, she, Ed and her daughters were able to move to a mansion in Sheepshead Bay, Brooklyn by the water.
* CallingParentsByTheirName: A clue that gave detectives an idea of what's going on is Donna's daughter calling Ed by his first name (indicating he's her stepfather.)
* ComfortingTheWidow: Ed [=McLean=] fell for the former Donna Mahar after being "assigned" her after her first husband Joe's death on 9/11.
* ContrivedCoincidence: The ferry crash happening at the same time Collette planned to kill Donna.
* DespairEventHorizon: Collette explained to Skoda that after the attacks, the world seemed ruined for her, even though her own husband was still alive. After it happened, she was left with PTSD, then Ed left her for Donna, she had to go back to work because he was only paying minimum child support and then he asked for sole custody due to being such an emotional wreck.
* DrivenToSuicide: The captain of the ferry attempts suicide in his cabin immediately after the crash.
* GoodCopBadCop: Fontana and Green attempt this routine on Collette.
* HeterosexualLifePartners: Ed and Joe, according to their former fellow firemen. Also their respective wives, Collette and Donna, according to their girlfriends.
* OneSteveLimit: Averted - Donna's and Collette's husbands, Joe and Ed, have the same first names as Fontana and Green.
* RailingKill: How Collette killed Donna; she pushed her over the railing of the ferry, she hit her head and drowned in the river.
* RippedFromTheHeadlines: The ferry crash bears resemblance to [[https://en.wikipedia.org/wiki/2003_Staten_Island_Ferry_crash an actual incident involving the Staten Island Ferry]] that happened roughly a year before the episode aired.
* SkewedPriorities: Fontana is more upset about his designer shirt getting ruined with bloodstains than he is about the ferry's captain, who has just attempted suicide.
* SurpriseCarCrash: Or shipwreck in this case: one minute, a man is arguing with a vendor over giving him a Canadian quarter for change, and the next, he and everyone else on the boat are violently tossed. Although he got knocked out by the impact, no one else but the primary victim was killed.
* SurvivorsGuilt: Joe died from the collapse of the North Tower, while Ed got out alive. According to Ed's testimony, this survivor's guilt is the main reason he retired from his job as firefighter.
* TimeDelayedDeath: Another firefighter neighbor of the suspect contracted leukemia due to cleaning up the aftermath of 9/11 and coming in contact with the millions of busted light bulbs and the mercury in them. His angry wife told the detectives that his death was imminent (to the point that the poor man had a hospital bed in the middle of his living room).
* TitleDrop: Referenced by a neighbor of Donna who says that the widows of those killed in 9/11 call themselves "the Dead Wives' Club."
* WeUsedToBeFriends: The people of Collette's neighborhood used to be very close before the terrorist attacks, but with death, divorce and remarriage, they all drifted apart.