Ball kicked dead through in-goal - IRB Laws of Rugby Union 2012

Definitions
22.1

Grounding the ball
22.2

Picking up the ball
22.3

Ball grounded by an attacking player
22.4

Other ways to score a try
22.5

Ball grounded by a defending player
22.6

Scrum, ruck or maul pushed into in-goal
22.7

Restarting after a touch down
22.8

Ball kicked dead through in-goal
22.9

Defending player in in-goal
22.10

Ball held up in-goal
22.11

Ball dead in in-goal
22.12

Ball or player touching a flag or flag (corner) post
22.13

Attacking infringement with scrum sanction
22.14

Defending infringement with scrum sanction
22.15

Doubt about grounding
22.16

Infringements in in-goal
22.17

Misconduct or unfair play in in-goal

22.8 BALL KICKED DEAD THROUGH IN-GOAL

If a team kicks the ball through their opponents’ in-goal into touch-in-goal or on or over the dead ball line, except by an unsuccessful kick at goal or attempted dropped goal, the defending team has two choices:
To have a drop-out,
or
To have a scrum at the place where the ball was kicked and they throw in.