It might say "Thor" on the cover, but there's only one real star of this book: the horse-faced Alien Thunder God, Beta Ray Bill. In a universe full of weird characters, Bill stands out as being particularly bizarre, and yet somehow his earnestness in the face of such an oddball setup makes him a strangely compelling fan-favorite.
Fraction has proven himself a capable scribe of Thor's world in the past, and he's no less at ease in this series, immediately writing the Skrull's trademark paranoia into the series a way that puts Thor's villains and supporting cast at the center, rather than the decidedly un-Asgardian Skrulls. For those wondering, this series prequels Thor's appearance in "Secret Invasion," so by using Beta Ray Bill as the focus, Fraction injects some uncertainty into the proceedings.
Meanwhile, a powerless Thor -- or rather Don Blake -- has to deliver a baby under dangerous circumstances having temporarily given up his hammer to Bill. While it's easy to see why Fraction has displaced the drama onto a new character to give the series a human angle, Blake's adventures aren't quite as meaningful to the audience without Thor in the mix. Unless there's a big twist coming, it's in danger of feeling a little too throwaway in the midst of the bigger fight.
Doug Braithwaite's artwork really brings the series to life, with some impressively action-filled panels that feel like they're leaping off the page. The scale of disaster in this comic is pretty big, but Braithwaite takes it all in stride. The coloring appears to have been done directly over the pencils, which is an effect that is often more miss than hit, but here it complements the disastrous events perfectly, bringing them into gritty, realistic focus.
Strangely, many of the "Secret Invasion" tie-ins are in danger of eclipsing the central series -- indeed, the majority of them already seem to contain more action than five issues of the parent series! While it's perhaps not that important in terms of the overall plot, Fraction promises to deliver a decent Thor read. Ultimately, that's what makes the crossovers work.