You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Plymouth

Context:
Plymouth lies between the River Plym to the east and the River Tamar to the west; both rivers flow into the natural harbour of Plymouth Sound. Since 1967, the unitary authority of Plymouth has included the, once independent, towns of Plympton and Plymstock which lie along the east of the River Plym. The River Tamar forms the county boundary between Devon and Cornwall and its estuary forms the Hamoaze on which is sited Devonport Dockyard.

Question:
In what body of water do the rivers Plym and Tamar meet?

Plymouth Sound