In the start (Season 1) Leo discovered Adam, Bree and Chase and the Lab Rats wanted to go to school and have a social start so season 1 had more of showing who they are thought in a season 1 episode Marcus had been showed to be a bad guy to Leo but not to the Lab Rats but in more episodes they start doing more life safe events and in Season 1 finial they go in space. In Season 2 in "Bionic Showdown" Marcus becomes a threat to all of the Lab Rats and Donald as it starts with more villains like: Marcus and Douglas then in the Season 2 final "No Going Back" the bad guys keep coming try to get them as all season finals end with a cliff hanger and the series premiere of Season 3 (Sink Or Swim) continuing from the season final.