Hey FernGully generation, you grew up and spawned some carbon footprints of your own (which, for the record, is the exact opposite of the vow you took in your younger years, the one where you promised to protect all rainforests from destructive humans, so way to go). Now you're wondering to yourself, "What, if anything, can I do this weekend besides take my 6-year-old to see The Hangover Part III? Is there, perhaps, a film almost just like FernGully that my entire family will find reasonably tolerable? Because I really liked FernGully." Well, you're in luck.
Epic isn't exactly like FernGully, though, because in that film the forest was endangered by logging and pollution, clear threats to a healthy environment. Epic, on the other hand, ramps up the fantasy mythology and kicks science in the teeth. A micro-level story of two-inch-high woodland creatures -- with meticulous, painstakingly detailed digital animation that turns the title into a clever Horton Hears a Who-style comment on scale -- it is actually anti-sense. The Leafmen (voiced by Colin Farrell and Josh Hutcherson) are tiny, human-like warriors who are committed to preserving their green paradise and they battle the Boggans (led by Christoph Waltz, villain voice lugged over from Inglourious Basterds). The Boggans are evil rot-creatures bent on destruction and that is bad. Allegedly. Because... see... that's sort of what happens in nature. And it's good. It's why things are green. Those things rot and feed the new plants and organisms. What I'm trying to say is that this story is full of lies.
Into this fake conflict arrives unhappy teen M.K. (Amanda Seyfried), shrunken by magic down to the size of the Leafmen, all the better to enlist the aid of her bumbling botanist father (Jason Sudeikis) in helping her new pals. She has to find the heroine within, facilitate some fighting, get into an inter-species romance and do the same thing every other reluctant protagonist does when faced with a battle between good and evil within the realm of the fantastic. So if you're keeping score, that's a plot that actively combats everything you'd actually want to teach your kid about protecting the environment, decorated with generic tropes from every other kid movie where the third act is about how great it is to fight in a war.
Comic relief from Aziz Ansari and Chris O'Dowd, as a slug and a snail, respectively, will almost make you forget that they're just the Rosencrantz and Guildenstern of this universe. There's also a thoroughly entertaining three-legged pug who barrels around the outskirts of the action. And when those three supporting characters are on screen, your attention immediately fires up and recognizes them as the most vibrant, nearly original creations in the film. Then they go away and you're left with the story whose ending you already know. Again.
Look, it could be worse. You could actually take the child to The Hangover Part III, for example, which would ruin both you and the kid. As it is, the only damage done here is the kind that repetitively generic children's films do: a slight dulling of the imagination, a lingering boredom, a wariness about all future kid-marketed entertainment. You'll live. So will the rainforest, no thanks to you.