"The Writing on the Wall" is the seventh episode of the second season of Agents of S.H.I.E.L.D..
The team discovers murder victims with the alien glyphs on them that Coulson's been etching. All of Coulson's secrets and lies come to a head.
A woman takes a man (the same man who covered his body in tattoos of the carvings Coulson had been making) back to her apartment. They make small talk over whether they already know each other. The man then takes off his shirt, revealing his tattoos, and kills the woman.
At the Playground, Coulson is busy making his carvings when Skye interrupts him. May, Morse, Hunter, and Triplett are on mission tracking down Grant Ward since he escaped his brother's custody. Skye lets Coulson know that one of her contacts shared with her a murder where the victim, the woman from before had Coulson's carvings carved into her corpse. Coulson recognizes the woman as a S.H.I.E.L.D. agent, but Skye finds that her record says she died five years ago. Coulson and Skye go to New York to investigate the scene, and find that she had made numerous paintings of the carvings before she died. They take the body back to the playground with her, where Simmons discovers she had the GH.325 serum in her blood, meaning she was a test subject in the T.A.H.I.T.I. project.
Realizing that the killer must be another T.A.H.I.T.I. test subject, Coulson puts himself in the memory machine to see if he can uncover his identity. The machine takes Coulson back to his days running the T.A.H.I.T.I. project, and forces him to re-witness the deterioration of the test subjects' mental states as they start making the carvings. Coulson solved the problem by having one of the lead scientists on the project implant the test subjects with false memories and give them a new life. As Coulson is reliving these memories, he starts convulsing and shouting how he needs to know about the carvings, forcing the others to take him out of the machine. They've narrowed the identity of the killer down to two former S.H.I.E.L.D. agents - Hank Thompson and Sebastian Derik. Skye privately tells the Director that he needs to stay behind, as his condition is worsening, but Coulson throws her into Ward's cell and leaves on his own.
After tracking Ward across the country, Hunter follows him to Boston, where he meets up with Bakshi at a bar. Inside, Ward offers to get Bakshi close enough to Coulson to "put a bullet in him point blank." Hunter lets the other agents on the hunt for him know about the meeting. They regroup in Boston, but once they go into the bar they find Ward killed the bartender and tied up Bakshi. The agents take him into their custody and bring him back to the Playground. Meanwhile, Coulson arrives at the house of Hank Thompson, and demands at gunpoint he reveal anything he knows about the carvings. Thompson tells him he couldn't help either of them as the killer, Sebastian Derik, sneaks up behind him and knocks him out. Derik then ties up Thompson, his family, and Coulson in the Thompson's barn, where Thompson and his son have built an elaborate model train set. Derik tells Coulson that he could bring back his memories by experiencing pain, which is why he was killing the former T.A.H.I.T.I. test subjects.
Couslon meanwhile realizes Thompson's train set was actually the runes, revealing they are meant to be viewed in three dimensions. As Derik is threatening Coulson with a knife, Thompson manages to cut out of his ties and free his family. Derik realizes his prisoner was escaping and throws his knife at him, but Thompson manages to catch the blade in mid-air and throw it back at him. Derik dives out of the way, but the knife cuts Coulson out of his ties. Derik attacks Coulson while he tries to get his assailant to realize what he has discovered about the carvings.
Coulson eventually gets Derik over a railing looking down on the train set, but Derik refuses to open his eyes. Simmons and Skye, who was freed after Simmons realized what Coulson had done arrive on the scene and pull their guns on Coulson and Derik, threatening to shoot both of them as Coulson may have gone crazy like Garrett had. Just as they are about to open fire, Derik opens his eyes and realizes what Coulson had been trying to show him - the carvings aren't as much a map as they are the blueprints to a city.
After turning Derik over to the authorities, Coulson and the team return to the Playground. Bakshi had since been placed in Ward's cell, and Coulson orders Skye to dig through his smart phone to uncover any information about Hydra and their plans. Coulson then debriefs his team on what he found out about the carvings. He no longer has the cravings to make them, and plans to use this information to get ahead of HYDRA in their race to uncover its secrets. Elsewhere, Ward shaves his head and facial hair and calls Bakshi's phone. Skye answers the call while pretending to be a HYDRA agent, but Ward immediately sees through her facade. He says she hopes she likes the "gift" he gave her with Bakshi, and promises that he'll be sending more gifts her way in the near future. Ward then hangs up, and starts making his way towards his brother.
- Clark Gregg as Phil Coulson
- Ming-Na Wen as Melinda May
- Brett Dalton as Grant Ward
- Chloe Bennet as Skye
- Iain De Caestecker as Leo Fitz
- Elizabeth Henstridge as Jemma Simmons
- Nick Blood as Lance Hunter
- B.J. Britt as Antoine Triplett
- Adrianne Palicki as Bobbi Morse/Mockingbird
- Henry Simmons as Alphonso Mackenzie
- Simon Kassianides as Sunil Bakshi
- Imelda Corcoran as Dr. Goodman
- Joel Gretsch as Cameron Klein/Hank Thompson
- Monica Lacy as Katie Thompson
- Monique Gabriela Curnen as Rebecca Stevens/Janice Robbins
- Bruno Amato as Bartender
- Carlos Campos as Lewis Seaver
- Michael Hanson as Patient #4
- Natalie Smyka as Patient #5
- Emily Maya Mills as Eliza
- Richie Cottrell as Graham
- Madison Lee as Lab Assistant
- Brian Van Holt as Sebastian Derik
Continuity and References to the Marvel Cinematic Universe
- Sunil Bakshi returns.
- New alien writings appear.
- Quinjet appears.
- Baron von Strucker is mentioned.
- The Obelisk is mentioned.
- Strategic Scientific Reserve logo appears.
- T.A.H.I.T.I. is mentioned.
- The Guest House, G.H., GH.325 and Memory Overwriting Machine are mentioned and appear in Coulson's memory.
- John Garrett is mentioned.
- Triskelion is mentioned.
- One of Janice Robbins paintings is signed as A Magical Place. It's the same answer Coulson gave every time he heard the word Tahiti in season 1.
- Daniel Whitehall is mentioned.
- Nick Fury is mentioned.
- Theta Brain-Wave Frequency Machine appears.
- The Avengers are mentioned.
- Captain America is mentioned and appears on propaganda poster in Coulson's office.
- Iron Man is mentioned.
- Christian Ward is mentioned and appears on the photo in a newspaper.
- HYDRA appears.
- It has been speculated that the city featured containing the symbols from the GH 325 formula is Attilan, the home base of the Inhumans, who share a history with the Kree.
- Skye mentions receiving information from a contact named "Micro," (who is) a bit of a crime enthusiast." This is arguably a reference to the Marvel Comics character David Linus "Microchip/Micro" Lieberman, an ally/friend of Frank Castle, A.K.A. The Punisher.
- The aerial shot used for the town in upstate New York is the same aerial shot that is used for Rosewood on "Pretty Little Liars".
- Cameron Klein is the grandson of Stanley Klein one of the Howling Camando's.
- When Coulson says "...Wondering if I was chasing windmills..." that is a reference to Don Quixote.
- The Blue alien is said to have been 1000's Of years old, which could foreshadow the Inhumans, a group of Homosapiens who were experimented by blue aliens called the Kree, by being given powers.
To be added