There's a new resident on "Sesame Street" in the 38th season of this long-running children's TV classic when Gordon and Susan's nephew, Chris Robinson (Christopher Knowings), moves onto the block and answers an ad to stock shelves at Hooper's Store. Later on, Telly and Baby Bear learn all about triangles; Rosita, Zoe and Abby get into a disagreement over a game of hide and seek; and Elmo talks like a baby to get attention.