The Mysterious Benedict Society, on Disney+
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Season One
Based on a series of books I've never read. An orphan named Reynard 'Reynie' Muldoon is encouraged by his tutor, Ms. Perumal, to take a test that might allow him to attend the prestigious Boatwright Academy. After a series of strange tests, only he and two other applicants remain: George 'Sticky' Washington (who has a photographic memory) and Kate Wetherall (who had previously run away to join the circus, and who always carries a bucket full of items she finds useful in various ways). It turns out the tests weren't actually for the Boatwright Academy, but rather were used by a man named Nicholas Benedict (Tony Hale) to recruit special children for a secret mission. He introduces them to the fourth member of their team, a younger girl named Constance Contraire (who seems to disdain pretty much everyone). She's the one who eventually comes up with the name "Mysterious Benedict Society" for the team.

There's a global crisis that causes everyone overwhelming anxiety, called "The Emergency", which Mr. Benedict believes is being caused by one man, the headmaster of a school called the L.I.V.E Institute, which is on an island. He wants the children to attend the school, learn who the headmaster is, and shut down his transmitter, which is sending subliminal messages on all media. It turns out the headmaster is L.D. Curtain, who happens to be Benedict's long lost twin brother (also played by Hale, though they look rather different). While the kids try to fit in at the Institute, which has lots of weird tests of its own, Mr. Benedict and his assistants look out for the kids from the mainland, frequently exchanging Morse code signals with them by flashlight. His assistants include Number Two (Kristen Schaal), Rhonda Kazembe, and a man named Milligan (who had lost his memory before being taken in by Benedict).

Well, I don't want to say much more about the plot, but I will say that the children's mission finally succeeds, after numerous setbacks. And... Dr. Curtain ends up going into exile with his adopted son, S.Q., and the head scientist of his organization, Dr. Garrison. While the season tells a complete story, and I wouldn't exactly call it a cliffhanger, Dr. Garrison does present Curtain with a new plan.

Season Two
I guess I don't want to spoil any details about this season's plot, but suffice to say the society must once again try to foil Dr. Curtain's new plan. There are also a few details about the end of season one that I had planned on revealing this season, but I guess I won't bother with that, either.