SuperQuark goes to Alaska, the place where, thanks to a protection policy, there is the highest concentration of grizzlies. These large bears can only find food for half the year, the other half they will have to live holed up, consuming the fat accumulated during the summer. For this reason it is important to be able to settle in the right territories, those richest in food. But since they all have the same need, competitions and clashes often arise. The BBC documentary makers remained isolated in these lands for 5 months, to film the grizzlies in action, also taking risks. The result is a very close portrait of these gigantic bears, also through a family story: that of a bear who must not only accumulate fat, but defend her cub. Next we will investigate the Rosetta space mission, the probe that will land on the tail of a comet next August. Then Paco Lanciano and Piero Angela in the studio will show how the Foucault pendulum works.