Well, it's going to have second season. From CBS Renews Amazon Deal for ‘Under the Dome’ Season 2:
Amazon will bring CBS’ summertime hit “Under the Dome” back for season 2, under a renewal that keeps the Internet company the exclusive online subscription-video distributor for the show.
Drama from Steven Spielberg’s Amblin Television, based on Stephen King’s bestselling novel, will return to the Eye for its second season in the summer 2014, as previously announced. Amazon’s Prime Instant Video service will offer the episodes four days after broadcast, as under their previous pact.
For CBS, the Amazon deal along with international pacts made “Under the Dome” profitable from the get-go, CEO Leslie Moonves said, speaking Wednesday at the Bank of America Merrill Lynch Media, Communications and Entertainment conference. “We basically were in profit regardless of what the network rating was,” he said. “Then when the network rating went through the roof — and it’s the highest-rated drama in the summer since 1991 — that became gravy.”