Te-kyu club has the only one tennis ball. They lost it because Kanae has hit it strongly. Then, they start to search the jungle for it, and they find a haunted place in the jungle.
Niconico Channel of the first season*: ch1212
You can read the original manga on Niconico Seiga: http://seiga.nicovideo.jp/book/series/21205?track=watch_page_52964_upper
*Has all the episodes of the first season.
Episodes 01-12 are the first season. BD of it is azB00A71INGA, and CD of Botsuraku Kizoku no Tame no Te-kyu** is azB00C5X1H66 .
The next episode is #13. Episodes 13-24 are the second season.
**The theme song of the first season.