Kirby comes to the Turtles’ universe after fleeing certain death in his alternate dimension earth.

Splinter and the Turtles suddenly went into exile to deal with their secondary mutations, leaving April behind without explanation.

In their absence, April gave up her news reporter work and became the sensei of the Kame-do dojo the turtles previously founded. Her students seem to be young kids, one of whom (Josh) has a crush on her.

The turtles return after a year and reconnect with April in their old sewer lair.

Spyder and his technograft henchmen follow Kirby to earth and sends his top talent (and possible lover) Miss D to hunt him down. His other technografts are called Bob, TonMan, and Crunch.

Miss D annihilates two “grungy redneck sanitation engineers” named Howard [Stern?] and Rush [Limbaugh?] who sexually harass her.

While the TMNT go out for a run and test their new morphed forms, April stays at the lair with Splinter (who keeps his morph secret but is struggling with spasms). Miss D invades the lair looking for Kirby and battles Splinter and April. When April breaks open Miss D’s exo-cat mask, she is revealed to be her exact doppleganger. Miss D is about to kill April when Kirby appears to chase her away.

The Turtles return and strike an alliance with Kirby to defeat Spyder and his techno-force

Kirby reveals that he is the last survivor of his brothers, all named after the four great Renaissance artists of his earth… Eisner, macfarland, Miller, and Kirby. They were trained by their master Sliver to defeat Spyder but failed. Their April apparently betrayed them and became loyal to Spyder.

Don finds a new lair, inside an 18th century sailing ship buried in the waterfront warehouse district. It can be accessed through a modified phone booth that opens up to a “turtle tube”

Spyder plans to unleash a swarm of millions of nanobots on our earth. He breaks into a government inventory storehouse to acquire the tech he needs. He then sets up base in a NY power sub-station, where the technografts charge their exo-suits at 30k volts. After that, he goes to a top-secret government lab at Penn Station, under Madison Square Garden.

Spyder finds an ex-KGB monster named Yuri hooked up to an iron lung (smoking is bad). Apparently Yuri once served Shredder and even went to his funeral too. He coerces him to give up a rom chip to program the nanobots.

Miss D gets mistaken for April by past co-workers and April’s dojo student Josh, which really makes her mad.

The Cyber version of Spyder traps Donatello into a computer hack… battle… event. All electro-mechanical items in the new lair get hacked and the turtles get jolted into morph loops. April breaks the trap thanks to her rubber-soled shoes. Somehow, a nanobot possesses a pizza/calzone and they freeze it. Don and Kirby use a Game Boy to reverse engineer it.

Spyder loves his coffee and tea. April gets suggestive with a security guard as a distraction tactic and makes a point to emphasize smoking is bad.

April gets briefly naked to slip out of a big ninja suit thing to save the Turtles from the “Stickypops” (explosive nanobot trap).

Splinter gifts April the moth-eaten gi of Tang Shen. April sews it up into a skintight ninja catsuit.

Kirby encourages the turtles that mastery over their morphs is the key to beating Spyder. He explains each morph form is a manifestation of their individual spirits.

Leo’s morphed form allows him to be launched as a “turtle puck”, which April rides on near the end.

April defeats Miss D and defends a weakened Splinter in a final battle after a Water Tower falls onto the villainess.

Splinter goes Beast Mode! He is frustrated he can’t do much action in his normal state and may hulk out on a rampage.

There is a big climatic scene against the Nanobots that seems to involve a cyber-space like portal.

In the end, April introduces her student to the TMNT.

No Casey Jones or Keno or Chief Sterns or Danny/Charles from what I can tell.