Marvel uses Free Comic Book Day to allow Jonathan Hickman one last trip back to the Future Foundation in "Secret Wars" #0. The short story -- an entertaining look at Valeria rounding up the troops to build the life raft that will ferry a sliver of humanity through the final incursion -- touches upon the greater plot Hickman has been telling for the past few years in the "Avengers" titles, but still requires readers to have some working knowledge of big players in the story.

Hickman has fun revisiting the kids and, strategically, it's a smart move to allow them to be a FCBD casual reader's inroad to this story. The characters bounce off one another very well and the dialogue is fun enough for adults to enjoy but also gives kids a point-of-view on the event from someone their own age. Valeria gives readers a quick summation of where the universe is at the onset of the story and jumps to the day of incursion quickly, ending with a gorgeous Paul Renaud double-page spread of the Ultimate Universe's Iron Man descending on the 616 universe superheroes, the final showdown between the worlds imminent. Renaud illustrates the tease from a ground-level perspective, framing 1610 Tony Stark with a sea of Earth's Mightiest Heroes rising to meet him, portending both hope from the ground and doom from above as Marvel moves into Hickman's final act.

The youngest of the Richards clan has taken it upon herself to help humanity not lose in this bleak event after she has crunched the numbers and realized there is no chance of actually winning in this situation. Renaud gives the three-year-old the poise and sass of someone eight times her age, confidence brimming from her body language as she breaks down the awful truth for her friends. The artist does a great job allowing the children some emotion while still making them look like children, something lost on many artists when illustrating the Future Foundation. The group of children was one of Hickman's best ideas during his time on the FF franchise, one ripe for the type of animated adaptation seen weekly on Disney XD.

The remaining pages of the comic are dedicated to a short tease of the hotly anticipated "Attack on Titan" crossover with Marvel that was announced late last year. It's a fun out-of-continuity short. Gerardo Sandoval's exaggerated anatomy, reminiscent of Joe Madureira and many other manga illustrators, works well for the sinewy, disturbing portrayals of the Titans. The pages are adrenaline-fueled action scenes as the Avengers attempt to stop several Titans surrounding New York before writer Hajime Isayama introduces the other hot Marvel property of the moment, the Guardians of the Galaxy. C.B. Cebulski, Jake Thomas and Tom Brevoort are all listed as having oversight and creative input on the story, so -- though it's light -- none of the characters are out of sorts in the way one would expect from this type of story.

Overall, Marvel's FCBD offering is an entertaining bag, with an entry level story for their complicated summer event and accessible base action for the fan curious as to what Comic Book Christmas is all about. None of the stories contained here are essential to a reader's greater understanding of the bigger narratives Marvel is working towards but are a fun presentation of what makes comic books so enjoyable.