Super Grover

Question: How did the bottle end up in lake Michigan if it was thrown in the Atlantic ocean?

Answer: None of the bottles ended up in Lake Michigan. Theresa is from Chicago, and when she and her son are at Boston Logan Airport she tells her ex-husband she'll be staying in Cape Cod for a few days, which is where she finds the bottle on the beach, along the Atlantic Coast. Then after the newspaper article, Theresa learns of another letter in a bottle, which Theresa notes as "bottle #2", and this bottle was found in Ocean City, Maryland, also along the Atlantic Coast. Catherine's letter in a bottle was found at Virginia's shoreline, so all of the bottles were found on the shores of the Atlantic Ocean.

Super Grover