According to Famitsu.com's summary, the trailer began by showing hunters gathering in what appeared to be a monster nest. A monster that looked like Rathian came swooping down from the sky, breathing fire.
The trailer continued with what looked like a new field -- a vast golden plain. As the hunters ran around the field, Famitsu's reporters spotted, as one would expect, Felynes following them.
Then, a new monster, which looked a bit like a fox, but whose movements were swift like a monkey. Standout features for the new monster appear to be big ears and claws.
Other monsters included Tigrex and Rathalos. Hunters were shown facing off against these beasts with new actions: one hunter jumping off a cliff into an attack, another attacking by climbing up a monster's back.
Before coming to a close with the Spring 2013 time frame, the trailer showed a silhouette of another new monster, this one large, and apparently swift.