gistfile1.txt

scala> case class Foo(bars: Seq[Int])
defined class Foo

scala> val foos = Seq(
     |   Foo(bars=Seq(1, 2, 3)),
     |   Foo(bars=Seq(4, 5, 6))
     | ) 
foos: Seq[Foo] = List(Foo(List(1, 2, 3)), Foo(List(4, 5, 6)))

scala> foos.map(_.bars).flatten
res1: Seq[Int] = List(1, 2, 3, 4, 5, 6)