Penny and Leonard come to terms with their feelings for each other, as Leonard and the guys prepare themselves for a three month long science trip.

Penny makes a surprising revelation on her second date with Stuart, then things begin to look up for Leonard. Meanwhile, Howard asks for his friends’ help when he discover a critical flaw in his project for NASA.

Raj and Leonard take a heartbroken Howard to LA, forcing Sheldon to bunk with Penny.

Howard and Leonard end up going to a bar’s Ladies’ Night.

A sexy woman moves into the apartment building, which makes Penny feel threatened.

Sheldon takes charge of Penny’s business selling hair products out of her apartment, then it gets out of hand!

The guys gets so thrilled when they find out that “Terminator: The Sarah Connor Chronicles Summer Glau” is also aboard their train to San Francisco.

Sheldon and Penny have a fight about Paintball, while Howard and Leslie have romance.

Leonard’s mom (Christine Baranski) visits him at his apartment and she ends up bringing him and Penny closer.

Penny gets Sheldon’s help with a financial crisis, but his solution leads to a confrontation between her ex-boyfriend.