My little brother, at 13 years old, without hearing any of the plot involving this movie, came up with this story in 20 seconds.
"A man and his dog go on a quest to find his wife's ring which was stolen from him"
This isn't a joke. I'm not lying to spite the movie. You can put together the rest if you've watched it. Not to mention it does a disservice to well developed and loved characters. You'd have to do some serious buildup to get
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Squidward of all people to start gushing over SpongeBob being gone. His buildup was "It just isn't the same here at the Krusty Krab without him" once and nothing else.
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It's lazy in the writing, it's poor in animation quality at noticeable places, and I wouldn't be surprised if they spent more money advertising it than making the show this movie is an advertisement for, "Camp Koral".
It's a disservice to the characters and to Hillenburg. It's not even worth paying to see how bad it is ironically, nor worth the two paid services (Amazon Prime Video and the Paramount one) that's required to watch it at home.
tl;dr (Too long; Didn't read)
Simply don't watch it. Not worth your money, after all it's solely what this movie seems to be after.