Hey guess what? There's a Season Pass for Halo 4! Who didn't see that coming? Before you pick up your torches and pitchforks, know that the Season Pass is for the War Games Maps of the game, which is the mulitplayer portion and NOT the Spartan Ops portion (which can be played solo or co-op).
The War Games Maps Pass costs $24.99 (2000 MSP) and provides access to three upcoming War Games map packs when they release. The Pass also offers two in-game helmets (Scanner and Strider) and a unique in-game emblem (Falcon).
The following are the details for each Map Pack:
Crimson Map Pack (December release timeframe)
Maps: Wreckage, Harvest, Shatter
Description: Witness the chaos of a clash of civilizations in Wreckage, with its blend of claustrophobic spaces and dangerous exposures and venture into the human colony environs of Harvest, and explore a human foray on an alien moon in Shatter.
Majestic Map Pack (February release timeframe)
Maps: Landfall, Monolith, Skyline
Description: Landfall’s emphasis is on infantry battles against a glittering ocean on a distant world, while Monolith exposes you to the naked vacuum of space – and the firepower of opposing teams, and Skyline’s distinctly industrial feel provides new challenges in somewhat familiar, but occasionally confined spaces.
Castle Map Pack (April release timeframe)
Maps: Daybreak, Outcast, Perdition
Description: Daybreak is set in a military facility against the backdrop of an idyllic mountain range, while Outcast plunges you into the warrens, canyons and arches of an alien edifice, and Perdition takes players into the heart of an urban sprawl, with tactical speed and situational awareness its key features.
So it's 9 maps for around $25, which isn't a bad deal if you compare it to how much map packs cost for Call of Duty games.