Children's cartoons often work on many levels, and I've long thought that "Thundercats," one of the most popular cartoons of the '80s, had a subtle sexual subtext to it, albeit buried so deep that no children (and few adults) could find it.

But the latest "Thundercats" comic book, published by Wildstorm, brings that subtext to the fore in a way that is impossible to miss and which has some readers up in arms.

© Copyright Warner Bros. and Ted Wolf ''Thundercats'' returns as a ''sad fanboy sex comic.''

As one online critic put it, "Thundercats: The Return," the new five-issue series by writer Ford Lytle Gilmore and artists Ed Benes and Joe Pimentel, is a "sad fanboy sex comic."

I'm not talking about pornography. Everything is implied rather than stated or depicted explicitly. But what is implied is a lot.

"Thundercats: The Return" is set several years after both the cartoon and an earlier comic-book series left off. The Thundercats' greatest foe, Mumm-Ra, has won. With the help of an army of mutants, he has overrun the Thundercats' home planet, Thundera, and trapped the Thundercats' leader, Lion-O, in another dimension, where Lion-O is unaware that years have elapsed back home.

In the four issues published so far, Lion-O returns from exile and reforms his core team of Thundercats, and while the Thundercats try to retake Thundera, Mumm-Ra stands around gloating about how everything, including Lion-O's return, is going according to plan.

It's not much of a story, but what you're probably wondering by now is, where is the sex?

Mumm-Ra has enslaved the surviving Thundercats and taken two teenaged ones, Wilykit and Wilykat, to his palace, where they serve him as pleasure slaves, to use the most charitable description.

They bathe him, change his bandages and sit chained and scantily dressed at his feet while he delivers tedious plot exposition. It's left to the reader to imagine what else they may be doing for him, but given that Mumm-Ra is a 1,000-year-old-plus mummified corpse, you probably don't want to think about it.

Meanwhile, another Thundercat, Cheetara, is in chains and left to the not-so-tender mercies of Mumm-Ra's mutant shock troops.

With all of this implied, non-consensual sex and bondage going on, "Thundercats: The Return" reads more like erotic fan fiction than it does an officially licensed Thundercats adventure. (A quick online search will turn up plenty of erotic Thundercats fan fiction. It isn't as if some fans haven't been thinking along similar lines.)

Others have also revived former children's characters in twisted, adult-oriented ways (see Cartoon Network's Adult Swim), but doing so is risky business. Wildstorm could have protected itself and comics retailers by giving "Thundercats: The Return" a "mature readers" label.

While most comic books are geared toward adults, most people nevertheless see comics as a children's medium. So, publishers must take care, especially when dealing with comics based on children's cartoons.

Sure, most people interested in reading "Thundercats" are those who watched the cartoon during the '80s. They are now in their 20s and 30s, and are beyond being scarred for life. But "Thundercats" reruns have aired on Cartoon Network during the past few years, and undoubtedly some children are interested in the title, especially since Wildstorm's first "Thundercats" comic-book series, published last year, was in keeping with the cartoon's child-friendly tone.

As it stands, "Thundercats: The Return" is one of the better-selling '80s nostalgia comics, behind "G.I. Joe" and "The Transformers." So, this may not be the last time we see old cartoon characters in new adult situations.