Did Mary, Queen of Scots, flee to England and remain a prisoner for 20 years?

Mary, Queen of Scots, had a pretty turbulent life, and her story is a great example of the complex relationship between England and Scotland in the 16th century. She was Catholic, and after being forced to abdicate the Scottish throne in 1567, she saw England as a place of refuge. Her cousin, Queen Elizabeth I, was on the English throne. However, Elizabeth viewed Mary as a threat because some Catholics believed Mary had a stronger claim to the English throne than Elizabeth herself. So, instead of offering sanctuary, Elizabeth had Mary imprisoned in 1568. She remained in custody for nearly two decades, moving between various castles and manor houses. Eventually, after being implicated in plots to assassinate Elizabeth, Mary was executed in 1587. So, the statement is true; Mary did flee to England and remained a prisoner for a significant period, almost 20 years, before her execution.
Mary's flight to England led to a long imprisonment, a dramatic chapter in history.