The season begins with the introduction of two new cases: when a school bus full of Neptune High students plunges off a cliff, killing almost everyone on board, Veronica Mars makes it her mission to discover why the bus crashed. Logan Echolls is accused of killing a Pacific Coast Highway biker gang member after drunkenly picking a fight with Eli "Weevil" Navarro and the PCHers.

The season revolves around Veronica Mars, a high school student and private investigator in the fictional Southern California seaside town of Neptune. When Veronica's best friend, Lilly Kane, is murdered, her life falls apart. Her father, County Sheriff Keith Mars, accuses Lilly's father of being involved in the murder. This provokes Neptune's wrath and Keith's ousting as sheriff in a recall election. Veronica's mother, Lianne, develops a drinking problem and leaves town. Veronica's "09er" friends—wealthy students from the fictional 90909 ZIP code—force her to choose between them and her father; she chooses her father. Keith opens a private investigation agency, Mars Investigations, where Veronica works part-time.

1947 年美國的 Roswell 正是全世界最注目的地方，美國軍方以氣象氣球的撞毀來解釋這個不可思議的事件。時間很快地過了四十年，四個從外星蛋殼中孵化，並混有人類 DNA 的外星人出世了。他們是外太空某星系的後裔，為了逃避戰亂而來到地球，務求在某天能夠有機會再次返回母星。
擁有正統皇室血統的 Max、他的妹妹 Isabel、他的保標 Michael 以及他的妻子 Tess 本過著低調及平凡的生活，但 Max 為了搶救被槍誤打中的女同學 Liz 而暴露了外星人身份，從此他們便與 Liz 及她的好友 Maria 及 Alex 等人於 Roswell 中逃避及對抗他們種族的敵人 ...
本劇集於 1999 年在美國開始播放，以外星人的元素來反影及描寫青少年在成長上所面對的各種問題，雖然此劇得獎不多，但其受歡迎程度不弱，尤其是以女歌手 Dido 所唱的主題曲已賣得滿堂紅。本劇於 2002 年播影完畢，合共有三個季度。