• Warning: Spoilers
    Neither was stolen from the other. Both came out at the same time, so that would be rather difficult. Do you have any idea how long it takes to get a TV series created, casted, pilot approved, pilot filmed, pilot aired, season approved, season filmed, and aired? It can't happen with two shows that debut within the same season for one to be a rip-off of the other (the same applies to those who still think that, for instance, "Babylon 5" is a rip-off of "Star Trek: Deep Space 9").

    Both series basically ripped (intentionally or otherwise) the plot of a novel published in 1998 entitled "Replay" (search for it on Amazon or BN.com). It was a serious drama with a fantasy element, and not at all a comedy. Good read, too, for those who like this sort of thing.

    I will agree, however, that "Do Over" was considerably superior to "That Was Then." They also weren't even all that similar in their basic plots, beyond the "adult relives youth" angle.

    Minor Spoiler Warnings for both series!:

    In "Do Over," the protagonist (Joel Larsen) found his 30-ish mind in his teenager body, and "stayed" there.

    In "That Was Then," the protagonist's adult mind went back and forth from his past high school body and time to the present, where he could see the results of his attempts to fix his own past and that of his family. Usually, he only made things worse. It was also more of a drama and less of a comedy than "Do Over."

    Note: opinions are opinions, but when you state a criminal charge such as plagiarism as fact, and do so in print (which includes online), you had better be able to back it up. Otherwise, you're committing libel, which is itself a serious crime.

    Saying that a TV series sucks is opinion. Saying that the acting is amateurish, the writing lame, the directing uninspired, etc. is opinion. Stating that one series is a rip-off of another is an accusation of the crime of plagiarism. Unless you know that to be true for a fact and can prove it (as in the series creator told you so in person, and you have a video of him doing so, or something in his handwriting confessing to it), don't make such charges.