[s1e21] Return To New York: Part 1 -

The group arrives at their old lair to find it deserted, realizing the Shredder believes they are dead—an advantage Splinter insists they use to launch a surprise attack.

April O'Neil acts as "Mission Control" from the lair, using her knowledge of Baxter Stockman's systems to infect the Foot’s communication network with a computer virus, effectively blinding their tactical coordination. [S1E21] Return to New York: Part 1

After initially being overwhelmed by the invisible attackers, the Turtles adapt. They use fire extinguishers to coat the area in dust, revealing the ninjas' silhouettes, and Donatello uses electro-magnetic shurikens to short-circuit their cloaking devices. Key Reveal & Cliffhanger The group arrives at their old lair to

The Turtles begin a systematic ascent of the skyscraper. They face an army of Foot Ninja and the formidable Foot Tech Ninjas , who use advanced cloaking technology to remain invisible. They use fire extinguishers to coat the area