A mysterious signal from the Wasteland is the setup for Mothership Zeta, Bethesda's space-themed add-on for Fallout 3. After following the signal to its source, a crashed UFO, the player is whisked into orbit and must figure out how to escape from alien captors who are loaded with high-tech gizmos. It's a wholly different take on the Fallout universe, but one that should have stayed more true to the source material.

Aliens aren't new to the Fallout world. Both of the original chapters of the Fallout franchise had random Easter eggs that weren't meant to be taken too seriously; one of them featured crashed spacecraft of dubious origin. Fallout 3 also drops in its own hint, although it's a fixed location that isn't so much of a joke as an homage to the original series' sense of humor.

The first Fallout had a flying saucer, two dead aliens next to it, the requisite ray gun and a velvet painting of Elvis, which was worth a few caps. The second one had a few tributes to "Star Trek," such as a crashed shuttle with several dead red shirts and a usable phaser. Even the venerable PC title, Wasteland, referenced a Martian campaign within its scene descriptions to throw off players who wanted to spoil the story by reading ahead. Knowing that each in-joke was part of the random humor that would occasionally make life a little more interesting in the wastes, these were taken in stride.

But with Mothership Zeta, Fallout 3 has essentially taken an Easter egg and made it into one, long, drawn-out joke. That's the same as LucasArts taking the death sticks guy from "The Phantom Menace" and turning him into an add-on for Star Wars: The Force Unleashed.

To date, most of the content has stayed in the postapocalyptic setting, which I'd thoroughly enjoyed. Even Fallout 3's earlier add-on, The Pitt, despite its technical issues and a few shortcomings with the story, was grounded in that theme. With Mothership Zeta, I had to throw out most of what I've come to expect in order to experience the add-on for what it was. It's conceivable that there are players out there who just want to vaporize aliens and want more awesome stuff to go along with it ... like me, on occasion. The '50s dabbled in sci-fi "what-ifs", so why not UFOs? Why not make something for Flash Gordon wannabes?

The problem isn't so much what fans of the older series might think. The fact is that the DLC comes across as a boring shoot-'em-up with a premise that's riddled with more holes than the moon. Operation: Anchorage's heavy focus on action tempered it with something directly related to the main arc of the Fallout universe, and it had interesting missions to boot. Mothership Zeta comes off as a linear and repetitive shooting gallery, and it feels more like an arcade version of X-Com than a story flush with postapocalyptic, face-melting material like Point Lookout's inbred mutants. I like a lot of action, but not in the overwhelmingly numbing doses that Mothership Zeta crams into its hallways.

Modders will find plenty of goodies in the new assets that Bethesda's gifted artists have put together:  sci-fi-inspired rib supports, Death Ray superweapon, and alien disintegrator rifles with radar dish-ended barrels. There's plenty for them to pore over, and Monty Haul players will relish scooping up every piece of abundant loot on the alien ship. The warbling sounds of the aliens' weapons add to the atmosphere along with a good deal of solid voice acting, but it all feels hollow, especially when the enemy is reduced to mere targets.

Even the humorous climax involving each of the characters only reminded me of the potential wasted on the monotonous combat that bombards the screen. You just get the feeling that this title doesn't have a lot to do with Fallout other than being based on a random encounter from the classics. Experienced characters will have a slightly easier time in getting through this, although it throws a few curve balls in the form of shielded baddies and the occasional violent abductee, but it doesn't matter when it begins to blur into a series of VATS screens that ask you to kill everything that moves.

The goal is simple: escape. To do so, the player will have to team up with an eclectic group of fellow abductees as they tackle tasks until they're ready to stage the inevitable takeover. There's quite a bit to see, but not necessarily a lot of variety in what they're able to do. Collectibles, aside from the massive arsenal of weapons that fill each level, also consist of often amusing recordings that players can find and listen to; if the recordings work, they usually contain the last words that the aliens' victims have left for posterity. I'm not sure if some of the dead space on a couple of these clips was intentional, but some seemed to consist of nothing but screeching alien chatter punctuated by odd interludes of silence.

At one point, the player is tasked with destroying several reactors to create a diversion that will allow him to spacewalk outside of the saucer and join the others. You can opt to have one of the abductees follow you into these areas and help out in combat duties, but you can't treat them as you would one of your followers on the surface. One of my temporary partners, a pre-Great War medic named Elliott who had fought at Anchorage before the bombs fell, would occasionally pick up and use an Alien Disintegrator on his own, but I didn't count on it since he'd just as often fight with a melee weapon instead.

Two of them are talented enough to make use of what you might find. The medic, if he survives, can create cryo-based grenades and mines as well as convert some of the strange alien bio-gel into something that you can use — assuming you don't mind the temporary side effects. Somah, the first buddy that you make on the mothership, can fix just about anything, as long as you have the caps. Personality-wise, this is about as deep as they get, providing some obligatory dialogue when the thin story demands it before they send you back out to kill more aliens and fill more containers with loot. Make the most out of it while you can because when this adventure ends, so does their ability to build and fix things.

The available gear is quite impressive, and the good news is that the aliens brought plenty of power units with them. From handheld Alien Atomizers to unique weapons like the Destabilizer rifle, players who are more interested in the gear will find this particular add-on to be a collector's paradise. There's so much of the stuff lying everywhere that at one point, I gave up trying to grab it all, and when I found out later that I could no longer access certain areas, I recognized it for the big mistake that it was. Did they decompress or something? I don't know; all I do know is that I left a lot of stuff behind newly locked doors and teleporters that have "conveniently" shut down. Fortunately, as part of the endgame and depending on whether they are alive, two of the abductees help out by staying aboard and scrounging up items that might be helpful.

For obvious reasons, I expected to see a limitation on the Repair skill. Apparently, both this production and that of the film, "Independence Day," share the idea that alien technology isn't so far removed from our own because repairing weird alien weapons is no problem for the player. There's no alien learning device in place to jam knowledge into the player's brain cells (unless that was supposed to be a side effect from what happens at the start of the game), which probably would have made too much sense amidst all of the shooting that occurs elsewhere in the game.

The new perk makes sense in terms of how it was gained, and that's the new Xenotech Expert perk, which makes you better at killing with exotic, otherworldly tech. Achievement hounds will also have four more to go for with this DLC, and if you survive through the end, you'll have a floating home to which you can return. 

That's another problem.

Home is a flying saucer — a huge alien ship loaded with bizarro tech — and it adds an uncomfortably overpowered aspect to the franchise, if not in terms of how it might fit in with the rest of the universe, then because of the heaping mountain of alien tech that could potentially flood the market on the surface. DMs are constantly reminded of the dangers of giving the player too much world-altering power, a lesson that should reverberate through every RPG designer's head for a variety of reasons, not the least of which is continuity. It would be as if the player and a cohort of his followers had taken over the Brotherhood's Citadel and made it their personal castle as part of the official arc. Fallout 3 wisely kept that from happening, but many of these considerations seem to be thrown out the window with Mothership Zeta.

Bethesda's creativity with the add-ons to Morrowind and Oblivion had always added something to their worlds, changing them in often dramatic ways and leaving us to wonder just what might lie in store for the world of Tamriel. The first few add-ons for Fallout 3 have done the same, subtly filling in some of the blanks left behind in the main story. Mothership Zeta feels like an unnecessary add-on.

Players who are more interested in stuff than substance will find plenty here to fill their pockets, but the title's sci-fi action and potential for humor are lost beneath the endless battle that nearly put me to sleep toward the end, thanks to a mouse-led metronome of clicks. It was all the more disappointing considering the other directions that could have been explored in the cold vacuum of space as offered up by the tantalizing hints that appeared in the first two Fallout titles. Fallout 3: Mothership Zeta is one side story that Wasteland warriors can afford to survive without.