The official website for the Haikyu!! Second Season television anime lists the anime at 25 episodes across nine Blu-ray/DVD volumes. Amazon Japan is also listing the nine volumes for pre-order.

The sequel series premiered in Japan on Saturday. Crunchyroll is streaming the anime in the United States, Canada, the United Kingdom, Ireland, Australia, New Zealand, South Africa, Scandinavia, Norway, Sweden, Finland, Denmark, the Netherlands, Turkey, and Latin America.

Crunchyroll describes the story:

After losing to Aoba Johsai at the Inter-High, the Karasuno High Volleyball Team is working their hardest toward the Spring Tournament. In the meantime, it's decided that they'll be heading to Tokyo for a training camp with Nekoma High and a handful of other powerful schools. They team is practicing hard, and not day during their run, Hinata and Kageyama get too excited and end up lost, and end up meeting someone rather unexpected...

[Via WTK]