My god, this is like the fifth thread on the topic.
You see what happened was, John Cena was a good man, living under the sea with his clown fish wife. But one day a predator attacked their home and killed all cena's eggs, except one. This led to Cena being overprotective of this last egg, having lost his wife too. But then, on the first day in school, his son Nemo is captured by an Austrailian, (most likely BkB Hulk) and then John Cena must travel the ocean to find his son.