back to the past

what happens when Evelyn goes back into the past when her dad and uncle was 18 and when Mateo was only 3 ,leo 2 and bryton 4 but what happens when tom and Bill also goes Into the past but in there old body's and they find Evelyn at there house but the only way for them to go back is when tom and Bill turns 21 and Evelyn see her mom but what if Evelyn discover of her mom secret that her mom neverd died