On the same day Abbey is diagnosed with ovarian cancer, she and her girlfriend, Miranda, are invited to dinner by Miranda's former self-help group to celebrate the return of their estranged friend, Scott, who left to discover the origins of their practices. Throughout the night, Abbey realizes that all is not as it seems, that no one is as who they've portrayed themselves to be...。故事围绕着五位主角展开。单身的泰德(乔什·拉德诺 Josh Radnor 饰)还在寻寻觅觅自己的真命天女,经历了多次失败的感情之后,他发现自己不再如以前一样有信念了。意外重逢了6年前的女友维多利亚。他想和维多利亚复合,却被告知对方将要订婚 。 另一方面,马修(杰森·席格尔 Jason Segel 饰)和莉莉(艾丽森·汉妮根 Alyson Hannigan 饰)惊喜发现莉莉怀孕了,这个新生命让他们既开心又紧张。巴尼(尼尔·帕特里克·哈里斯 Neil Patrick Harris 饰)则忙于挽回前女友诺拉,诺拉决定再给巴尼一次机会,于是他们重新在一起。罗宾(寇碧·史莫德斯 Cobie Smulders 饰)醋意大发,她发现自己还爱着巴尼…… 本剧以“老妈”是谁为最大悬念,只知道泰德在巴尼的婚礼上遇见这位神秘的真命天女,她究竟是谁?。