Peter Falk said in an interview, "This is the part of a lifetime." It's also the performance of a lifetime. In the first scene it's obvious this is super entertainment and a great relationship between the two leading characters.
The story begins when Rocky (Falk) is 75 years old. The roommate he takes in is his orphaned grandson Michael (D.B. Sweeney). Other relatives fear Rocky will not survive much longer and the young Michael will again lose the parent in his life. Typically, Rocky says, "He stays here and that's that." Rocky is a strong, work ethic Polish American. He and his grandson share the classified help wanted section throughout their 30 years together.
Rocky's dominant personality cuts both ways. It gives him strength and a clear direction in life and it also makes life miserable for his grandson. At 80 he breaks the nose of a baseball fan who steals a foul ball from Michael's glove. He also disturbs and moralizes over his grandson's love affair with Beth (Julianne Moore).
The film is all Falk's. His antics as a cantankerous old man bring smiles and tears throughout the film. Falk is totally convincing as a stubborn old man with a devilish sense of humor.
His journey from 77 years to 107 is filled with the joy and pain of daily living, generational differences and the bonds of love which make life worth living. Falk probably has an Academy Award nomination waiting for him at next year's ceremony.