Bunnicula travels back in time to try and keep Mina's project from being destroyed.
It's Friday the 13th, and Chester and Harold (and Mina's dad, Arthur, apparently) had already been through an unlucky streak and were covered in bandages by the time Bunnicula woke up to start his evening. Bunnicula claims that he never had a bad day in his life, thus he believes Friday the 13th wouldn't effect him, but he ended up jinxing it for himself when he trips on a chest and accidentally unleashed a screaming banshee, who knocks him dizzy. After that, he goes upstairs to play/cuddle with Mina, who is too busy working on a paper-mache bust of George Washington ("the guy on the dollar bill") and is too busy to play out of the fear that flunking art class would land her in summer school... she isn't to busy to take a much needed shower, though. While she was gone, Bunnicula notices his stomach growling and goes into the kitchen for his evening carrot, only to find out that Mina's dad was eating the only fresh carrot that was left and had left him a moldy one in the fridge. Had lost his appetite, Bunnicula then goes out to help Harold receive his favorite stick from the other side of the Orlock gates, only for him to get splashed by a passing car and rained on in the process. Just when Bunnicula thought things couldn't get any worse, he ended up stepping in some glue that Mina spilled, causing him to stumble and ruin her art project, thus causing her to cry. Harold tries to comfort Bunnicula, saying that it isn't like he could go back in time to fix it. Just then, Lugosi pops out of the porch herb garden and suggests that his "master" eats thyme, which will allow the vampire rabbit to relive Friday the 13th as often as he has to in order to have a perfect day. Chester, feeling that it is a bad idea, gets into an argument with Lugosi, but Bunnicula, willing to try anything to give himself and Mina a better day, bites into the herb and wakes up back in his coffin... on the evening of Friday the 13th!
At first, Bunnicula is thrilled that he's going to correct his day, though he had to go through more time loops then expected to keep several of his misfortunes from happening, but the most challenging of all is keeping Mina's art project safe, as each alternative timeline keeps giving him a different reason for such a task to be impossible--each one more extreme then the last-- until he ended up setting Orlock Apartments on fire while trying to protect the bust from a fire-breathing dragon. It was at that point that Bunnicula confesses to Chester and Harold that he's been reliving the same day over and over, and when Lugosi shows up and insists that he does it again (thus triggering another argument with Chester), Harold gave the vampire rabbit good advice: that sometimes, one has to accept that things aren't always going to go the one's way, and that it cannot be changed, but if today is bad, tomorrow might turn out great. Realizing that Harold was right, Bunnicula decides to accept his bad day, thus eats the thyme one last time so that the dragon fire never happened.
Waking up in his coffin on the evening of Friday the 13th, Bunnicula, with a brave yet heavy heart, allows everything to go wrong exactly as it did the first time-- he even actually eats the rotten carrot and gets indigestion-- right up to the point where Mina's project breaks and she ends up fussing over summer school. Rather then go back in time again, Bunnicula merely lies on the floor in sadness and defeat. Time finally moves forward, and on Monday evening Bunnicula is still upset about what happened on his bad day, but allows Chester and Harold to comfort him during TV time while they wait for Mina to come home. When she had returned, she came back with great news: her art teacher loved the ruined sculpture enough to give an "A" on the assignment, saying it looked like Benjamin Harrison (a president that Mina doesn't even know), so there is no need to worry about summer school after all. As Mina hugs all three of her pets and claimed today might be their lucky day, it is clear by the smiles on their faces that they couldn't agree more.
- In one of the timelines, Mina saw Bunnicula in his triclops form.
- Mina doesn't know her presidents rather well.
- While eating the carrot that Bunnicula wanted, Arthur Monroe (Mina's dad) says "What's up doc?" to someone on the other end of the phone line. That particular quote is the catchphrase of Bugs Bunny, who (like Bunnicula) is a rabbit animated by Warner Brothers studios.
- There are many time travel stories in media that involve reliving the same day over and over, including "Groundhogs Day", "Happy Death Day", "12:01", and "The Last Day of Summer". Keeping up with the theme, Bunnicula tries to give himself and Mina a good day on Friday the 13th.