Nice Suit

Playing IMPS on BBO, with a pickup partner, Vul vs Not, my partner picked up AKQJT6 J9532 43 -- in first seat. She decided to open 1S (which I totally agree with) and I bid 2D. You had said you are playing 2/1 as a general approach, but did not discuss too much else.

She now bid 2S, which I like, to emphasize that Spade suit. I bid 3D, she now bid 3H, and I bid 3S. She decided she liked her hand and cue bid 4C, which went double on her left, 4H by me, P to her. What to do now. Here is the auction

S W N E
1S P 2D P
2S P 3D P
3H P 3S P
4C * 4H P
?

At this point, she bid 6S, showing confidence in partner. The opening lead was a Spade and this dummy tracked. 53 A AKJT95 JT73. When the Q of Diamonds dropped, the hand quickly made 7. Shows the power of fits and good suits. I really like the 6S bid, although it gets a little more exciting if W can ever find a Heart lead to knock out the entry.

Here is his hand he had to lead from on this auction, any clues as to that being the killer. 874 K8 876 KQ952. Looks to me like leading the Heart could be the only way it makes on a lot of hands.