When the CSIs track down a suave and charming hitman, their investigation uncovers a conspiracy with far-reaching implications.
Sweetheart week hits Degrassi and Adam is shocked by his newfound connection with Fiona. That is until Fiona's drinking habits become out of control. He's willing to turn a blind eye if it means they get to spend time together, but begins to wonder if he's the problem.
After Holly J. tells Adam about Fiona's previous drinking problems, he ignores it, and believes that Fiona loves him without being drunk. When Fiona goes to far with the champagne, he, along with the support of Holly J. and Fiona's mother, takes Fiona to an intervention, where she agrees to go to rehab.
Rex and Six attempt to retrieve nuclear material from a research sub. They encounter an underwater colony of Evos.
The Joes try to destroy a bio-viper facility, but are hindered by Firefly, a saboteur for Cobra.
Fanboy and Chum Chum play cupids when Dollar-nator falls in love with Oz's new robot librarian, Julie Android.
Van Pelt's actions are called into question when a witness is murdered while she is assigned to his protection.
Tom tries to get back at Ron by going out on a date with Ron's ex-wife Tammy, while Leslie tries to protect Ron from falling prey to her charms. Meanwhile, April is assigned to work with Chris.
Todd leads anger-management training to improve the staff's customer-service skills, but he's surprised to learn that Gupta is in need of the most help. Elsewhere, Madhuri receives a Valentine's Day gift from a secret beau.
Stefan and Elena get away for what they hope will be a romantic weekend at the Gilbert family lake house, not realizing that they’ve been followed. Jenna starts to worry that Alaric isn’t being honest with her. Jules explains the importance of the sun and moon curse to Tyler, but leaves out an important detail. Damon attends a tea at the Historical Society in order to talk to Elijah, but Elijah isn’t giving up any secrets. With help from Caroline and Jeremy, Bonnie uses deceptive measures to get shocking new information out of Luka. Finally, Tyler offers Matt some relationship advice.
Mini is under threat. When Grace brings Franky into the charity fashion show, Mini sacks them both, and re-imagines the show in her own image to cement her power.
A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.
On Valentine's Day, Troy and Abed compete for the attention of an assistant librarian, while Britta tries to show she's open-minded about lesbians.
A BMX rider’s remains are discovered on the roof of a warehouse after a failed bike stunt. While Booth and Brennan interrogate the victim’s fellow riders, Hodgins and newly mellowed “squint” Fisher identify the numerous fractures in the victim’s skeletal structure, and Angela recreates the series of events that led to the fatal accident. Meanwhile, Sweets turns to Booth for advice about his relationship with Daisy, and Booth makes a decision about his relationship with Hannah.
The staff grows increasingly uncomfortable with Michael and Holly's PDAs. Jim and Pam regret a champagne luncheon. Andy horns in on a romantic treasure hunt Gabe arranged for Erin.
Thatcher Grey, Meredith and Lexie's father, returns to Seattle Grace with stomach pains and a new, twenty-something tattooed girlfriend, Danielle. Meanwhile, Alex clashes with the new OB, Dr. Lucy Fields, over a patient and Mark places Jackson on his service in exchange for information on Lexie.
Lee dreams of a perfect life with Lucy, but can the reality ever match up?
The Crime Scene crew investigates the gruesome murder of a high-powered, widowed lawyer, while Ray faces that it is time to move on from his old life.
Jack and a very pregnant Avery take a romantic break in Canada. When Avery goes into labor, the power couple desperately scramble to not give birth to a Canadian. Meanwhile, Liz's getaway with Carol gets grounded, literally, when their plane collects dust on the tarmac. And Tracy is an EGOT winner, but with that comes overwhelming demands.
Charlotte's attacker, Lee Henry, arrives at St. Ambrose Hospital, injured by his girlfriend and in need of urgent care, and Sam and Charlotte must decide whether or not to save his life. Meanwhile, Susan's health takes a turn for the worse, and Addison's mother, Bizzy, begs her daughter to do everything in her power to help.