“INVADERS, Y’ALL,” Part Three Roland Rocketfeller is alive! But not so well. Can his family reach him before a bloodthirsty sabretooth tiger does? Meanwhile, in the present, the rest of the family faces off with the Jupiterians and the perils of socializing in the 21st century. Plus: a new breed of time hunter has also found the Rocketfellers…but what do they want with them?