We knew this was coming.
Celestia is seen talking to someone we don't know. They have a conversation, in which the person orders Celestia to get a pendant from his daughter, Cadence. It is also learned that Celestia has another child, which she was forced to give up because it wasn't an alicorn.
Thus, she heads off and murders both Cadance and Shining Armor, taking the pendant from them.
DMS and Luna both get a call from Cadance before she was murdered. They charge to the scene to find them dead. Luna points out that the pendant Cadance had was stolen.
During the funeral, Celestia appears to taunt them. She then sicks robot walkers on them, but they are quickly defeated. It then shows Celestia talking to 3 other ponies- A dark, powerful being named Avalon Darkhorse, a geeky techno hacker named Gizmo, and a strange voodoo priest named Acolan. She orders all 3 of them to do different tasks to effectively ruin DMS and Luna.
Elsewhere, DMS and Luna return home, to discover their house occupied by unknown troops. Soon enough, they are captured by the troops and knocked out. They wake up in a plane flying high in the sky. Celestia and Avalon appear to try and kill them, but Luna breaks free, ramming her horn through Celestia's eye. Avalon flees with Celestia, and Luna and DMS escape the plane, blowing it up.
After they land, DMS calls up both ZX and LD, and learns that they too have had a similar problem. Only they were seeing two different sets of ponies in their castles- Green robe wearing freaks and cyber pony ninjas, respectively. They call up Lazro, who was doing something... intimate... with Iala at the time. So they head to his house.
Back at Celestia's headquarters, Celestia storms in and acts like a bitch again. BIG SURPRISE. She comes up with a plan, and Gizmo is tasked with carrying it out.
Back at Lazro's house, DMS, Luna, ZX, LD, and Twilight, who was wtih ZX, head in. They catch Lazro after he's finished, and like DMS after he's had sex, is talking rapidly. DMS also learns that Solaria, their daughter, is okay. She was staying at Lazro's house because of the funeral. They decide to call up both S17 and Pinkie Pie for help. Afterwards, they head to bed. A pregnant Chrysalis, who was wandering around dying, smells the love coming from the house (as a result of DMS and Luna fucking) and sneaks over to get food she desperately needs.
As Pinkie walks to Lazro's house, she is attacked by the same cyber pony ninjas that invaded LD's castle. They attack the house, and the gang fends them off, along with a mercenary that Celestia hired, named 'Joker'. Afterwards, they discover Chrysalis near the house. Luna wants to kill her, but DMS spares her since she is pregnant with his own child, allowing her to stay with them.
The next morning, after some banter involving Chrysalis, a completely glitched up Lazro, and pigeons, DMS gets a contact from a stallion named Code Breaker, who's a hacker. Code tells DMS that he hates Gizmo, the leader of the cyber pony ninjas that attacked them last night. He also tells them about who her leaders are.
Avalon Darkhorse was a dark ruler who went to war with Celestia some time ago. Celestia banished him to Tartarus after defeating him, but brought him back to use as a commander for her forces. Gizmo was a professional hacker who managed to single handedly ruin a massive company in Equestria. He was later discovered and arrested, but, like Avalon, was released to be used as a commander. Acolan was a dark voodoo priest. He was notorious for sacrificing ponies to dark gods that didn't exist. He was also a well known drug dealer. He was arrested, but like Gizmo and Avalon, was released to be used in her army.