A mysterious woman poses some serious concerns for our web-slinging hero.
At the Coffee Shoppe, the place is jumping with music and dancing and girls. Peter is off in a corner reading the paper about the upcoming test of a new proton device. [Way to blend in] His classmates try to convince him to join in, but he claims he's not in the mood. They begin to tease him that he'd rather read about scientific discoveries than have fun. Peter begins to lecture them on the importance of science but is cut off.
A blond woman named Carol walks up to him and confesses to overhearing their conversation. She expresses and interest in science as well and asks if she can join him. Peter agrees, but realizes his spider-sense is tingling [That ain't your spider-sense, Parker] They find an immediate connection and agree to meet back here tomorrow.
Later while out on patrol, Spider-Man discovers Carol is stealing electronic components. When he tries to stop her, he is shocked to learn she has spider-powers as well. She traps him in her web and leaves, promising that it will dissolve soon.
The next night, Carol doesn't show up at the Coffee Shoppe. A disappointed Peter changes to Spider-Man and goes out on patrol, finding her in the Warehouse District. After accidentally breaking the device she stole, Carol confesses to knowing his identity. She has spider-sense as well - which is how they recognize each other. At this point a globe-shaped spaceship appears. After a brief battle with other spider-men, they escape and lead him on a cross-country chase that ends in a cave in what appears to be the southwest. [No exaggeration here. I think that at some point, he should have lost them due to the lack of skyscrapers in West Virginia.]
The spider-people finally realize that he's not going to stop [Oh, now you do?] and use one of their alien rays to transform a random group of boxes into a giant spider. Spider-Man webs the creature in one of the tunnels and continues. He eventually finds their hidden city, but is captured and brought before their leader, who happens to be Carol's father.
The old man and Carol explain that they are explorers from another planet. They crashed on Earth many years ago. The laws of their civilization prevent them from taking over the world or interfering with any civilization [Found a loophole with the breaking and entering thing, didn't you?] They have finally made contact with their home planet and will be rescued by transport beam in two hours. This coincides with the test of the proton device which will destroy their colony. They can't leave as the radiation released will kill them. Carol was sent to gather [steal] components to remotely attach their machine to the . That is now infeasible. The only option left is to attach their black box to the proton device. It will decrease the radiation released to a survivable level. However this must be done in person and there is not enough time.
Spider-Man argues that he can try since he's partly to blame for their situation. When they refuse he grabs the box and makes a mad dash for the proton device. Inspired by his bravery, they help him defeat the giant spider still lurking in the cave. He attaches the device and stops the test. At the appointed time, the beam picks up the alien buildings and returns them to their home planet.
Ehhhhh. Very rarely do they go through so much effort and the end result is still boring. There's an upper limit to the members of the spider-population. You can have Spider-Man (obviously), Madame Web, at most two Spider-Women, and only one Tarantula. That's it. They went overboard with the spider-planet. This isn't Thor nor are these characters Asgardians.
1 web. If you can get past the concept that an entire planet full of spider-people exist and have been stranded on Earth for an indeterminate amount of time and that their laws of non-interference are selectively enforced it's not a bad episode. They tried to do something different - perhaps a little too different.
It holds together well enough to entertain small children and very bored adults. Outside of those cases, this is something that could be skipped entirely.
I think that part of the problem with these full-length episodes is that they simply reuse too much material. They'll animate a few (emphasis) new segments and wear them out as well as overuse the stock footage. Since this takes up a significant amount of the episode, the quality of the episode drops quickly.