Angela Merkel triumphed in her fourth straight national victory. But the far-right Alternative for Germany party loomed over the celebration. What began as a Euro-skeptic group, morphed into an anti-immigrant, anti-Muslim movement after Merkel allowed one-point-three million refugees over the border. Now the AfD has the third largest number of MPs in the Bundestag. And the party's leaders say the government should get ready for tough times. The question is, will Merkel bend to the pressure?