"Secret Invasion" is a major crossover comic book storyline published by Marvel Comics in 2008. Written by Brian Michael Bendis and illustrated by Leinil Francis Yu, the eight-issue limited series ran from April through December of that year, accompanied by numerous tie-in issues across other Marvel titles. The story's central premise is a long-term, covert infiltration of Earth by the Skrulls, a race of alien shapeshifters who have secretly replaced many of the world's superheroes with impostors over a period of years, leading to a massive overt invasion.
The storyline was seeded by Bendis years in advance, with subtle hints placed in earlier works such as "Secret War" and "New Avengers." The event's tagline, "Who do you trust?," captured the paranoia and suspense that defined the narrative, as heroes and villains alike were revealed to be Skrull sleeper agents. The motivation for the invasion was tied to the destruction of the Skrull Empire in the 2007 "Annihilation" storyline, with the Skrulls viewing Earth as their religious and rightful home.
"Secret Invasion" was a significant commercial and critical event for Marvel, reshaping the landscape of the Marvel Universe by calling into question the true identities of beloved characters and altering team dynamics for years to come. It remains one of the most ambitious and memorable crossover events of the modern era of comics.