In this lively family adventure, Alvin, Simon, and Theodore embark on a cross-country journey to prevent their guardian, Dave, from proposing to his new girlfriend, which they fear will lead to them gaining a terrible stepbrother. The film features the voice talents of Justin Long, Matthew Gray Gubler, and Jesse McCartney, with Jason Lee reprising his role as Dave. Directed by Walt Becker, the movie combines humor and heart, appealing to both children and adults. For those interested, it can be viewed for free on 123Movies / Movies123.